Conjugated polymers

ABSTRACT

The invention relates to novel conjugated polymers containing one or more repeating units derived from indacenodibenzothiophene or dithia-dicyclopenta-dibenzothiophene, to methods for their preparation and educts or intermediates used therein, to polymer blends, mixtures and formulations containing them, to the use of the polymers, polymer blends, mixtures and formulations as organic semiconductors in organic electronic (OE) devices, especially in organic photovoltaic (OPV) devices and organic photodetectors (OPD), and to OE, OPV and OPD devices comprising these polymers, polymer blends, mixtures or formulations.

TECHNICAL FIELD

The invention relates to novel conjugated polymers containing one ormore repeating units derived from indacenodibenzothiophene ordithia-dicyclopenta-dibenzothiophene, to methods for their preparationand educts or intermediates used therein, to polymer blends, mixturesand formulations containing them, to the use of the polymers, polymerblends, mixtures and formulations as organic semiconductors in organicelectronic (OE) devices, especially in organic photovoltaic (OPV)devices and organic photodetectors (OPD), and to OE, OPV and OPD devicescomprising these polymers, polymer blends, mixtures or formulations.

BACKGROUND

Organic semiconducting (OSC) materials are receiving growing interestmostly due to their rapid development in the recent years and thelucrative commercial prospects of organic electronics.

One particular area of importance is organic photovoltaics (OPV).Conjugated polymers have found use in OPVs as they allow devices to bemanufactured by solution-processing techniques such as spin casting, dipcoating or ink jet printing. Solution processing can be carried outcheaper and on a larger scale compared to the evaporative techniquesused to make inorganic thin film devices. Currently, polymer basedphotovoltaic devices are achieving efficiencies above 8%.

In order to obtain ideal solution-processible OSC molecules two basicfeatures are essential, firstly a rigid π-conjugated core unit to formthe backbone, and secondly a suitable functionality attached to thearomatic core unit in the OSC backbone. The former extends π-π overlaps,defines the primary energy levels of the highest occupied and lowestunoccupied molecular orbitals (HOMO and LUMO), enables both chargeinjection and transport, and facilitates optical absorption. The latterfurther fine-tunes the energy levels and enables solubility and henceprocessability of the materials as well as π-π interactions of themolecular backbones in the solid state.

A high degree of molecular planarity reduces the energetic disorder ofOSC backbones and accordingly enhances charge carrier mobilities.Linearly fusing aromatic rings is an efficient way of achieving maximumplanarity with extended π-π conjugation of OSC molecules. Accordingly,most of the known polymeric OSCs with high charge carrier mobilities aregenerally composed of fused ring aromatic systems and aresemicrystalline in their solid states. On the other hand, such fusedaromatic ring systems are often difficult to synthesize, and do alsooften show poor solubility in organic solvents, which renders theirprocessing as thin films for use in OE devices more difficult. Also, theOSC materials disclosed in prior art still leave room for furtherimprovement regarding their electronic properties.

Thus there is still a need for organic semiconducting (OSC) polymerswhich are easy to synthesize, especially by methods suitable for massproduction, show good structural organization and film-formingproperties, exhibit good electronic properties, especially a high chargecarrier mobility, a good processibility, especially a high solubility inorganic solvents, and high stability in air. Especially for use in OPVcells, there is a need for OSC materials having a low bandgap, whichenable improved light harvesting by the photoactive layer and can leadto higher cell efficiencies, compared to the polymers from prior art.

It was an aim of the present invention to provide compounds for use asorganic semiconducting materials that are easy to synthesize, especiallyby methods suitable for mass production, and do especially show goodprocessibility, high stability, good solubility in organic solvents,high charge carrier mobility, and a low bandgap. Another aim of theinvention was to extend the pool of OSC materials available to theexpert. Other aims of the present invention are immediately evident tothe expert from the following detailed description.

The inventors of the present invention have found that one or more ofthe above aims can be achieved by providing conjugated polymerscontaining one or more repeating units based on a fusedindacenodibenzothiophene (IDDBT) unit of structure (I) ordithia-dicyclopenta-dibenzothiophene (TTDBT) of structure (II) as shownbelow, wherein X is for example CRR or C═CRR, and R is for examplealkyl, or derivatives thereof.

Surprisingly it was found that these enlarged fused ring systems, andthe polymers containing them, still show sufficient solubility inorganic solvents, which can also be further improved by introducingalkyl or alkylidene substituents onto the indacene unit. Both the homo-and co-polymers can be prepared through known transition metal catalysedpolycondensation reactions. As a result the polymers of the presentinvention were found to be attractive candidates for solutionprocessable organic semiconductors both for use in transistorapplications and photovoltaic applications. By further variation of thesubstituents on the fused aromatic ring system, the solubility andelectronic properties of the monomers and polymers can be furtheroptimised.

SUMMARY

The invention relates to conjugated polymers comprising one or moredivalent units of formula I

wherein

-   X¹ and X² independently of each other denote C(R¹R²), C═C(R¹R²),    Si(R¹R²) or C═O,-   A¹ is

-    wherein the thiophene ring may also be substituted in 3-position by    a group R¹,-   A² is

-    wherein the thiophene ring may also be substituted in 3-position by    a group R¹,-   B is

-   R¹ and R² independently of each other denote H, straight-chain,    branched or cyclic alkyl with 1 to 30 C atoms, in which one or more    CH₂ groups are optionally replaced by —O—, —S—, —C(O)—, —C(S)—,    —C(O)—O—, —O—C(O)—, —NR⁰—, —SiR⁰R⁰⁰—, —CF₂—, —CHR⁰═CR⁰⁰—, —CY¹═CY²—    or —C≡C— in such a manner that O and/or S atoms are not linked    directly to one another, and in which one or more H atoms are    optionally replaced by F, Cl, Br, I or CN, or denote aryl,    heteroaryl, aryloxy or heteroaryloxy with 4 to 20 ring atoms which    is optionally substituted, preferably by halogen or by one or more    of the aforementioned alkyl or cyclic alkyl groups,-   Y¹ and Y² independently of each other denote H, F, Cl or CN,-   R⁰ and R⁰⁰ independently of each other denote H or optionally    substituted C₁₋₄₀ carbyl or hydrocarbyl, and preferably denote H or    alkyl with 1 to 12 C-atoms.

The invention further relates to a formulation comprising one or morepolymers comprising a unit of formula I and one or more solvents,preferably selected from organic solvents.

The invention further relates to the use of units of formula I aselectron donor units in semiconducting polymers.

The invention further relates to conjugated polymers comprising one ormore repeating units of formula I and/or one or more groups selectedfrom aryl and heteroaryl groups that are optionally substituted, andwherein at least one repeating unit in the polymer is a unit of formulaI.

The invention further relates to monomers containing a unit of formula Iand further containing one or more reactive groups which can be reactedto form a conjugated polymer as described above and below.

The invention further relates to semiconducting polymers comprising oneor more units of formula I as electron donor units, and preferablyfurther comprising one or more units having electron acceptorproperties.

The invention further relates to the use of the polymers according tothe present invention as electron donor or p-type semiconductor.

The invention further relates to the use of the polymers according tothe present invention as electron donor component in a semiconductingmaterial, formulation, polymer blend, device or component of a device.

The invention further relates to a semiconducting material, formulation,polymer blend, device or component of a device comprising a polymeraccording to the present invention as electron donor component, andpreferably further comprising one or more compounds or polymers havingelectron acceptor properties.

The invention further relates to a mixture or polymer blend comprisingone or more polymers according to the present invention and one or moreadditional compounds which are preferably selected from compounds havingone or more of semiconducting, charge transport, hole or electrontransport, hole or electron blocking, electrically conducting,photoconducting or light emitting properties.

The invention further relates to a mixture or polymer blend as describedabove and below, which comprises one or more polymers of the presentinvention and one or more n-type organic semiconductor compounds,preferably selected from fullerenes or substituted fullerenes.

The invention further relates to a formulation comprising one or morepolymers, formulations, mixtures or polymer blends according to thepresent invention and optionally one or more solvents, preferablyselected from organic solvents.

The invention further relates to the use of a polymer, formulation,mixture or polymer blend of the present invention as charge transport,semiconducting, electrically conducting, photoconducting or lightemitting material, or in an optical, electrooptical, electronic,electroluminescent or photoluminescent device, or in a component of sucha device or in an assembly comprising such a device or component.

The invention further relates to a charge transport, semiconducting,electrically conducting, photoconducting or light emitting materialcomprising a polymer, formulation, mixture or polymer blend according tothe present invention.

The invention further relates to an optical, electrooptical, electronic,electroluminescent or photoluminescent device, or a component thereof,or an assembly comprising it, which comprises a polymer, formulation,mixture or polymer blend, or comprises a charge transport,semiconducting, electrically conducting, photoconducting or lightemitting material, according to the present invention.

The optical, electrooptical, electronic, electroluminescent andphotoluminescent devices include, without limitation, organic fieldeffect transistors (OFET), organic thin film transistors (OTFT), organiclight emitting diodes (OLED), organic light emitting transistors (OLET),organic photovoltaic devices (OPV), organic photodetectors (OPD),organic solar cells, laser diodes, Schottky diodes, and photoconductors.

The components of the above devices include, without limitation, chargeinjection layers, charge transport layers, interlayers, planarisinglayers, antistatic films, polymer electrolyte membranes (PEM),conducting substrates and conducting patterns.

The assemblies comprising such devices or components include, withoutlimitation, integrated circuits (IC), radio frequency identification(RFID) tags or security markings or security devices containing them,flat panel displays or backlights thereof, electrophotographic devices,electrophotographic recording devices, organic memory devices, sensordevices, biosensors and biochips.

In addition the compounds, polymers, formulations, mixtures or polymerblends of the present invention can be used as electrode materials inbatteries and in components or devices for detecting and discriminatingDNA sequences.

DETAILED DESCRIPTION

The polymers of the present invention are easy to synthesize and exhibitadvantageous properties. They show good processability for the devicemanufacture process, high solubility in organic solvents, and areespecially suitable for large scale production using solution processingmethods. At the same time, the co-polymers derived from monomers of thepresent invention and electron donor monomers show low bandgaps, highcharge carrier mobilities, high external quantum efficiencies in BHJsolar cells, good morphology when used in p/n-type blends e.g. withfullerenes, high oxidative stability, and a long lifetime in electronicdevices, and are promising materials for organic electronic OE devices,especially for OPV devices with high power conversion efficiency.

The units of formula I are especially suitable as (electron) donor unitin both n-type and p-type semiconducting compounds, polymers orcopolymers, in particular copolymers containing both donor and acceptorunits, and for the preparation of blends of p-type and n-typesemiconductors which are suitable for use in BHJ photovoltaic devices.

The repeating units of formula I contain an enlarged system of fusedaromatic rings, which creates numerous benefits in developing novel highperformance OSC materials. Firstly, a large number of fused aromaticrings along the long axis of the core structure increases the overallplanarity and reduces the number of the potential twists of theconjugated molecular backbone. Elongation of the π-π structure ormonomer increases the extent of conjugation which facilitates chargetransport along the polymer backbone. Secondly, the high proportion ofsulphur atoms in the molecular backbone through the presence of fusedthiophene rings promotes more intermolecular short contacts, whichbenefits charge hopping between molecules. Thirdly, the large number offused rings leads to an increased proportion of ladder structure in theOSC polymer main chain. This forms a broader and more intense absorptionband resulting in improved solar light harvesting compared with priorart materials. Additionally but not lastly, fusing aromatic rings canmore efficiently modify the HOMO and LUMO energy levels and bandgaps ofthe target monomer structures compared with periphery substitutions.

Besides, the polymers of the present invention show the followingadvantageous properties:

-   i) The indacenodibenzothiophene (IDDBT) and    dithia-dicyclopenta-dibenzothiophene (TTDBT) units are expected to    exhibit a co-planar structure. Adopting a highly co-planar structure    in the solid-state is beneficial for charge transport.-   ii) The IDDBT and TTDBT core structures can be solubilised by both    four alkyl groups or two alkylidene groups. Compared with the    tetra-alkyl analogues, the dialkylidene substituted IDDBT-based    molecules and polymers are expected to possess a higher degree of    planarity. This is due to the sp² carbon atoms in the alkylidenes    which allow the alkyl chains to take an in-plane configuration. This    configuration reduces the inter-planar separation of the π-π    backbones, and improves the degree of inter-molecular π-π    interactions.-   iii) The optoelectronic properties of conjugated polymers vary    significantly based upon the degree of extended conjugation between    the consecutive repeating units and the inherent electron densities    within the polymer backbones. By fusing additional aromatic rings    along the long axis, the π-conjugation of the resultant molecules    and consequently the polymers can be extended and the number of the    inter-unit twists in the backbone can be reduced-   iv) Additional fine-tuning and further modification of the    indacenodibenzothiophene (IDDBT) and    dithia-dicyclopenta-dibenzothiophene (TTDBT) cores or    co-polymerisation with appropriate co-monomer(s) can afford    conjugated polymers that are suitable as organic semiconductors for    organic electronic applications.

The synthesis of the unit of formula I, its functional derivatives,compounds, homopolymers, and co-polymers can be achieved based onmethods that are known to the skilled person and described in theliterature, as will be further illustrated herein.

As used herein, the term “polymer” will be understood to mean a moleculeof high relative molecular mass, the structure of which essentiallycomprises the multiple repetition of units derived, actually orconceptually, from molecules of low relative molecular mass (Pure Appl.Chem., 1996, 68, 2291). The term “oligomer” will be understood to mean amolecule of intermediate relative molecular mass, the structure of whichessentially comprises a small plurality of units derived, actually orconceptually, from molecules of lower relative molecular mass (PureAppl. Chem., 1996, 68, 2291). In a preferred meaning as used hereinpresent invention a polymer will be understood to mean a compoundhaving >1, i.e. at least 2 repeat units, preferably ≧5 repeat units, andan oligomer will be understood to mean a compound with >1 and <10,preferably <5, repeat units.

Further, as used herein, the term “polymer” will be understood to mean amolecule that encompasses a backbone (also referred to as “main chain”)of one or more distinct types of repeat units (the smallestconstitutional unit of the molecule) and is inclusive of the commonlyknown terms “oligomer”, “copolymer”, “homopolymer” and the like.Further, it will be understood that the term polymer is inclusive of, inaddition to the polymer itself, residues from initiators, catalysts andother elements attendant to the synthesis of such a polymer, where suchresidues are understood as not being covalently incorporated thereto.Further, such residues and other elements, while normally removed duringpost polymerization purification processes, are typically mixed orco-mingled with the polymer such that they generally remain with thepolymer when it is transferred between vessels or between solvents ordispersion media.

As used herein, in a formula showing a polymer or a repeat unit, likefor example a unit of formula I or a polymer of formula III or IV, ortheir subformulae, an asterisk (*) will be understood to mean a chemicallinkage to an adjacent unit or to a terminal group in the polymerbackbone. In a ring, like for example a benzene or thiophene ring informula I, an asterisk (*) will be understood to mean a C atom that isfused to an adjacent ring.

As used herein, the terms “repeat unit”, “repeating unit” and “monomericunit” are used interchangeably and will be understood to mean theconstitutional repeating unit (CRU), which is the smallestconstitutional unit the repetition of which constitutes a regularmacromolecule, a regular oligomer molecule, a regular block or a regularchain (Pure Appl. Chem., 1996, 68, 2291). As further used herein, theterm “unit” will be understood to mean a structural unit which can be arepeating unit on its own, or can together with other units form aconstitutional repeating unit.

As used herein, a “terminal group” will be understood to mean a groupthat terminates a polymer backbone. The expression “in terminal positionin the backbone” will be understood to mean a divalent unit or repeatunit that is linked at one side to such a terminal group and at theother side to another repeat unit. Such terminal groups include endcapgroups, or reactive groups that are attached to a monomer forming thepolymer backbone which did not participate in the polymerisationreaction, like for example a group having the meaning of R⁵ or R⁶ asdefined below.

As used herein, the term “endcap group” will be understood to mean agroup that is attached to, or replacing, a terminal group of the polymerbackbone. The endcap group can be introduced into the polymer by anendcapping process. Endcapping can be carried out for example byreacting the terminal groups of the polymer backbone with amonofunctional compound (“endcapper”) like for example an alkyl- orarylhalide, an alkyl- or arylstannane or an alkyl- or arylboronate. Theendcapper can be added for example after the polymerisation reaction.Alternatively the endcapper can be added in situ to the reaction mixturebefore or during the polymerisation reaction. In situ addition of anendcapper can also be used to terminate the polymerisation reaction andthus control the molecular weight of the forming polymer. Typical endcapgroups are for example H, phenyl and lower alkyl.

As used herein, the term “small molecule” will be understood to mean amonomeric compound which typically does not contain a reactive group bywhich it can be reacted to form a polymer, and which is designated to beused in monomeric form. In contrast thereto, the term “monomer” unlessstated otherwise will be understood to mean a monomeric compound thatcarries one or more reactive functional groups by which it can bereacted to form a polymer.

As used herein, the terms “donor” or “donating” and “acceptor” or“accepting” will be understood to mean an electron donor or electronacceptor, respectively. “Electron donor” will be understood to mean achemical entity that donates electrons to another compound or anothergroup of atoms of a compound. “Electron acceptor” will be understood tomean a chemical entity that accepts electrons transferred to it fromanother compound or another group of atoms of a compound. (see also U.S.Environmental Protection Agency, 2009, Glossary of technical terms,http://www.epa.gov/oust/cat/TUMGLOSS.HTM

As used herein, the term “n-type” or “n-type semiconductor” will beunderstood to mean an extrinsic semiconductor in which the conductionelectron density is in excess of the mobile hole density, and the term“p-type” or “p-type semiconductor” will be understood to mean anextrinsic semiconductor in which mobile hole density is in excess of theconduction electron density (see also, J. Thewlis, Concise Dictionary ofPhysics, Pergamon Press, Oxford, 1973).

As used herein, the term “leaving group” will be understood to mean anatom or group (which may be charged or uncharged) that becomes detachedfrom an atom in what is considered to be the residual or main part ofthe molecule taking part in a specified reaction (see also Pure Appl.Chem., 1994, 66, 1134).

As used herein, the term “conjugated” will be understood to mean acompound (for example a polymer) that contains mainly C atoms withsp²-hybridisation (or optionally also sp-hybridisation), and whereinthese C atoms may also be replaced by hetero atoms. In the simplest casethis is for example a compound with alternating C—C single and double(or triple) bonds, but is also inclusive of compounds with aromaticunits like for example 1,4-phenylene. The term “mainly” in thisconnection will be understood to mean that a compound with naturally(spontaneously) occurring defects, which may lead to interruption of theconjugation, is still regarded as a conjugated compound.

As used herein, unless stated otherwise the molecular weight is given asthe number average molecular weight M_(n) or weight average molecularweight M_(W), which is determined by gel permeation chromatography (GPC)against polystyrene standards in eluent solvents such astetrahydrofuran, trichloromethane (TCM, chloroform), chlorobenzene or1,2,4-trichlorobenzene. Unless stated otherwise, 1,2,4-trichlorobenzeneis used as solvent. The degree of polymerization, also referred to astotal number of repeat units, n, will be understood to mean the numberaverage degree of polymerization given as n=M_(n)/M_(U), wherein M_(n)is the number average molecular weight and M_(U) is the molecular weightof the single repeat unit, see J. M. G. Cowie, Polymers: Chemistry &Physics of Modern Materials, Blackie, Glasgow, 1991.

As used herein, the term “carbyl group” will be understood to meandenotes any monovalent or multivalent organic radical moiety whichcomprises at least one carbon atom either without any non-carbon atoms(like for example —C≡C—), or optionally combined with at least onenon-carbon atom such as N, O, S, P, Si, Se, As, Te or Ge (for examplecarbonyl etc.). The term “hydrocarbyl group” will be understood to meana carbyl group that does additionally contain one or more H atoms andoptionally contains one or more hetero atoms like for example N, O, S,P, Si, Se, As, Te or Ge.

As used herein, the term “hetero atom” will be understood to mean anatom in an organic compound that is not a H- or C-atom, and preferablywill be understood to mean N, O, S, P, Si, Se, As, Te or Ge.

A carbyl or hydrocarbyl group comprising a chain of 3 or more C atomsmay be straight-chain, branched and/or cyclic, including spiro and/orfused rings.

Preferred carbyl and hydrocarbyl groups include alkyl, alkoxy,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy,each of which is optionally substituted and has 1 to 40, preferably 1 to25, very preferably 1 to 18 C atoms, furthermore optionally substitutedaryl or aryloxy having 6 to 40, preferably 6 to 25 C atoms, furthermorealkylaryloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy andaryloxycarbonyloxy, each of which is optionally substituted and has 6 to40, preferably 7 to 40 C atoms, wherein all these groups do optionallycontain one or more hetero atoms, preferably selected from N, O, S, P,Si, Se, As, Te and Ge.

The carbyl or hydrocarbyl group may be a saturated or unsaturatedacyclic group, or a saturated or unsaturated cyclic group. Unsaturatedacyclic or cyclic groups are preferred, especially aryl, alkenyl andalkynyl groups (especially ethynyl). Where the C₁-C₄₀ carbyl orhydrocarbyl group is acyclic, the group may be straight-chain orbranched. The C₁-C₄₀ carbyl or hydrocarbyl group includes for example: aC₁-C₄₀ alkyl group, a C₁-C₄₀ fluoroalkyl group, a C₁-C₄₀ alkoxy oroxaalkyl group, a C₂-C₄₀ alkenyl group, a C₂-C₄₀ alkynyl group, a C₃-C₄₀allyl group, a C₄-C₄₀ alkyldienyl group, a C₄-C₄₀ polyenyl group, aC₂-C₄₀ ketone group, a C₂-C₄₀ ester group, a C₆-C₁₈ aryl group, a C₆-C₄₀alkylaryl group, a C₆-C₄₀ arylalkyl group, a C₄-C₄₀ cycloalkyl group, aC₄-C₄₀ cycloalkenyl group, and the like. Preferred among the foregoinggroups are a C₁-C₂₀ alkyl group, a C₁-C₂₀ fluoroalkyl group, a C₂-C₂₀alkenyl group, a C₂-C₂₀ alkynyl group, a C₃-C₂₀ allyl group, a C₄-C₂₀alkyldienyl group, a C₂-C₂₀ ketone group, a C₂-C₂₀ ester group, a C₆-C₁₂aryl group, and a C₄-C₂₀ polyenyl group, respectively. Also included arecombinations of groups having carbon atoms and groups having heteroatoms, like e.g. an alkynyl group, preferably ethynyl, that issubstituted with a silyl group, preferably a trialkylsilyl group.

The terms “aryl” and “heteroaryl” as used herein preferably mean amono-, bi- or tricyclic aromatic or heteroaromatic group with 4 to 30ring C atoms that may also comprise condensed rings and is optionallysubstituted with one or more groups L,

wherein L is selected from halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN,—C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H,—SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, P-Sp-, optionally substituted silyl, orcarbyl or hydrocarbyl with 1 to 40 C atoms that is optionallysubstituted and optionally comprises one or more hetero atoms, and ispreferably alkyl, alkoxy, thiaalkyl, alkylcarbonyl, alkoxycarbonyl oralkoxycarbonyloxy with 1 to 20 C atoms that is optionally fluorinated,and R⁰, R⁰⁰, X⁰, P and Sp have the meanings given above and below.

Very preferred substituents L are selected from halogen, most preferablyF, or alkyl, alkoxy, oxaalkyl, thioalkyl, fluoroalkyl and fluoroalkoxywith 1 to 12 C atoms or alkenyl, alkynyl with 2 to 12 C atoms.

Especially preferred aryl and heteroaryl groups are phenyl in which, inaddition, one or more CH groups may be replaced by N, naphthalene,thiophene, selenophene, thienothiophene, dithienothiophene, fluorene andoxazole, all of which can be unsubstituted, mono- or polysubstitutedwith L as defined above. Very preferred rings are selected from pyrrole,preferably N-pyrrole, furan, pyridine, preferably 2- or 3-pyridine,pyrimidine, pyridazine, pyrazine, triazole, tetrazole, pyrazole,imidazole, isothiazole, thiazole, thiadiazole, isoxazole, oxazole,oxadiazole, thiophene, preferably 2-thiophene, selenophene, preferably2-selenophene, thieno[3,2-b]thiophene, thieno[2,3-b]thiophene,furo[3,2-b]furan, furo[2,3-b]furan, seleno[3,2-b]selenophene,seleno[2,3-b]selenophene, thieno[3,2-b]selenophene, thieno[3,2-b]furan,indole, isoindole, benzo[b]furan, benzo[b]thiophene,benzo[1,2-b;4,5-b′]dithiophene, benzo[2,1-b;3,4-b′]dithiophene, quinole,2-methylquinole, isoquinole, quinoxaline, quinazoline, benzotriazole,benzimidazole, benzothiazole, benzisothiazole, benzisoxazole,benzoxadiazole, benzoxazole, benzothiadiazole, all of which can beunsubstituted, mono- or polysubstituted with L as defined above. Furtherexamples of aryl and heteroaryl groups are those selected from thegroups shown hereinafter.

An alkyl or alkoxy radical, i.e. where the terminal CH₂ group isreplaced by —O—, can be straight-chain or branched. It is preferablystraight-chain, has 2, 3, 4, 5, 6, 7 or 8 carbon atoms and accordinglyis preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl,ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, or octoxy,furthermore methyl, nonyl, decyl, undecyl, dodecyl, tridecyl,tetradecyl, pentadecyl, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy ortetradecoxy, for example.

An alkenyl group, wherein one or more CH₂ groups are replaced by —CH═CH—can be straight-chain or branched. It is preferably straight-chain, has2 to 10 C atoms and accordingly is preferably vinyl, prop-1-, orprop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, 2-, 3- or pent-4-enyl,hex-1-, 2-, 3-, 4- or hex-5-enyl, hept-1-, 2-, 3-, 4-, 5- orhept-6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- or oct-7-enyl, non-1-, 2-, 3-,4-, 5-, 6-, 7- or non-8-enyl, dec-1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- ordec-9-enyl.

Especially preferred alkenyl groups are C₂-C₇-1E-alkenyl,C₄-C₇-3E-alkenyl, C₅-C₇-4-alkenyl, C₆-C₇-5-alkenyl and C₇-6-alkenyl, inparticular C₂-C₇-1E-alkenyl, C₄-C₇-3E-alkenyl and C₅-C₇-4-alkenyl.Examples for particularly preferred alkenyl groups are vinyl,1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl,3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl,4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groupshaving up to 5 C atoms are generally preferred.

An oxaalkyl group, i.e. where one CH₂ group is replaced by —O—, ispreferably straight-chain 2-oxapropyl (=methoxymethyl),2-(=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3-, or4-oxapentyl, 2-, 3-, 4-, or 5-oxahexyl, 2-, 3-, 4-, 5-, or 6-oxaheptyl,2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonylor 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl, for example. Oxaalkyl, i.e.where one CH₂ group is replaced by —O—, is preferably straight-chain2-oxapropyl (=methoxymethyl), 2-(=ethoxymethyl) or 3-oxabutyl(=2-methoxyethyl), 2-, 3-, or 4-oxapentyl, 2-, 3-, 4-, or 5-oxahexyl,2-, 3-, 4-, 5-, or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-,3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-, 7-, 8- or9-oxadecyl, for example.

In an alkyl group wherein one CH₂ group is replaced by —O— and one by—C(O)—, these radicals are preferably neighboured. Accordingly theseradicals together form a carbonyloxy group —C(O)—O— or an oxycarbonylgroup —O—C(O)—. Preferably this group is straight-chain and has 2 to 6 Catoms. It is accordingly preferably acetyloxy, propionyloxy, butyryloxy,pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl,butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl,2-propionyloxy-ethyl, 2-butyryloxyethyl, 3-acetyloxypropyl,3-propionyloxypropyl, 4-acetyloxybutyl, methoxycarbonyl, ethoxycarbonyl,propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl,ethoxy-carbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl,2-(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl,2-(propoxy-carbonyl)ethyl, 3-(methoxycarbonyl)propyl,3-(ethoxycarbonyl)propyl, 4-(methoxycarbonyl)-butyl.

An alkyl group wherein two or more CH₂ groups are replaced by —O— and/or—C(O)O— can be straight-chain or branched. It is preferablystraight-chain and has 3 to 12 C atoms. Accordingly it is preferablybis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl,4,4-bis-carboxy-butyl, 5,5-bis-carboxy-pentyl, 6,6-bis-carboxy-hexyl,7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-carboxy-nonyl,10,10-bis-carboxy-decyl, bis-(methoxycarbonyl)-methyl,2,2-bis-(methoxycarbonyl)-ethyl, 3,3-bis-(methoxycarbonyl)-propyl,4,4-bis-(methoxycarbonyl)-butyl, 5,5-bis-(methoxycarbonyl)-pentyl,6,6-bis-(methoxycarbonyl)-hexyl, 7,7-bis-(methoxycarbonyl)-heptyl,8,8-bis-(methoxycarbonyl)-octyl, bis-(ethoxycarbonyl)-methyl,2,2-bis-(ethoxycarbonyl)-ethyl, 3,3-bis-(ethoxycarbonyl)-propyl,4,4-bis-(ethoxycarbonyl)-butyl, 5,5-bis-(ethoxycarbonyl)-hexyl.

A thioalkyl group, i.e where one CH₂ group is replaced by —S—, ispreferably straight-chain thiomethyl (—SCH₃), 1-thioethyl (—SCH₂CH₃),1-thiopropyl (=—SCH₂CH₂CH₃), 1-(thiobutyl), 1-(thiopentyl),1-(thiohexyl), 1-(thioheptyl), 1-(thiooctyl), 1-(thiononyl),1-(thiodecyl), 1-(thioundecyl) or 1-(thiododecyl), wherein preferablythe CH₂ group adjacent to the sp² hybridised vinyl carbon atom isreplaced.

A fluoroalkyl group is preferably perfluoroalkyl C_(i)F_(2i+1), whereini is an integer from 1 to 15, in particular CF₃, C₂F₅, C₃F₇, C₄F₉,C₅F₁₁, C₆F₁₃, C₇F₁₅ or C₈F₁₇, very preferably C₆F₁₃, or partiallyfluorinated alkyl, in particular 1,1-difluoroalkyl, all of which arestraight-chain or branched.

Alkyl, alkoxy, alkenyl, oxaalkyl, thioalkyl, carbonyl and carbonyloxygroups can be achiral or chiral groups. Particularly preferred chiralgroups are 2-butyl(=1-methylpropyl), 2-methylbutyl, 2-methylpentyl,3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, in particular2-methylbutyl, 2-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy,2-ethyl-hexoxy, 1-methylhexoxy, 2-octyloxy, 2-oxa-3-methylbutyl,3-oxa-4-methyl-pentyl, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl,2-decyl, 2-dodecyl, 6-meth-oxyoctoxy, 6-methyloctoxy,6-methyloctanoyloxy, 5-methylheptyloxy-carbonyl, 2-methylbutyryloxy,3-methylvaleroyloxy, 4-methylhexanoyloxy, 2-chloropropionyloxy,2-chloro-3-methylbutyryloxy, 2-chloro-4-methyl-valeryloxy,2-chloro-3-methylvaleryloxy, 2-methyl-3-oxapentyl, 2-methyl-3-oxahexyl,1-methoxypropyl-2-oxy, 1-ethoxypropyl-2-oxy, 1-propoxypropyl-2-oxy,1-butoxypropyl-2-oxy, 2-fluorooctyloxy, 2-fluorodecyloxy,1,1,1-trifluoro-2-octyloxy, 1,1,1-trifluoro-2-octyl,2-fluoromethyloctyloxy for example. Very preferred are 2-hexyl, 2-octyl,2-octyloxy, 1,1,1-trifluoro-2-hexyl, 1,1,1-trifluoro-2-octyl and1,1,1-trifluoro-2-octyloxy.

Preferred achiral branched groups are isopropyl, isobutyl(=methylpropyl), isopentyl (=3-methylbutyl), tert. butyl, isopropoxy,2-methyl-propoxy and 3-methylbutoxy.

In a preferred embodiment, R^(1,2) are independently of each otherselected from primary, secondary or tertiary alkyl or alkoxy with 1 to30 C atoms, wherein one or more H atoms are optionally replaced by F, oraryl, aryloxy, heteroaryl or heteroaryloxy that is optionally alkylatedor alkoxylated and has 4 to 30 ring atoms. Very preferred groups of thistype are selected from the group consisting of the following formulae

wherein “ALK” denotes optionally fluorinated, preferably linear, alkylor alkoxy with 1 to 20, preferably 1 to 12 C-atoms, in case of tertiarygroups very preferably 1 to 9 C atoms, and the dashed line denotes thelink to the ring to which these groups are attached. Especiallypreferred among these groups are those wherein all ALK subgroups areidentical.

—CY¹¹═CY¹²— is preferably —CH═CH—, —CF═CF— or —CH═C(CN)—.

As used herein, “halogen” includes F, Cl, Br or I, preferably F, Cl orBr.

A used herein, —CO—, —C(═O)— and —C(O)— will be understood to mean acarbonyl group, i.e. a group having the structure

Preferably X¹ and X² in formula I denote C(R¹R²), C═(R¹R²), Si(R¹R²) orC═O very preferably C(R¹R²) or C═(R¹R²).

Preferably the units of formula I are selected from the followingformulae:

wherein X¹ and X² have the meanings of formula I as given above andbelow, wherein the terminal thiophene rings may also be substituted in3-position by a group R¹. In a preferred embodiment one or both terminalthiophene rings are substituted in 3-position by a group R¹.

In the units of formula I and its preferred subformulae, R¹ and R²preferably denote straight-chain, branched or cyclic alkyl with 1 to 30C atoms which is unsubstituted or substituted by one or more F atoms.

Further preferably one of R¹ and R² is H and the other is different fromH, and is preferably straight-chain, branched or cyclic alkyl with 1 to30 C atoms which is unsubstituted or substituted by one or more F atoms.

Further preferably R¹ and/or R² are independently of each other selectedfrom the group consisting of aryl and heteroaryl, each of which isoptionally fluorinated, alkylated or alkoxylated and has 4 to 30 ringatoms.

If R¹ and/or R² in formula I denote substituted aryl or heteroaryl, itis preferably substituted by one or more groups L, wherein L is selectedfrom P-Sp-, F, Cl, Br, I, —OH, —CN, —NO₂, —NCO, —NCS, —OCN, —SCN,—C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NR⁰R⁰⁰, C(═O)OH, optionallysubstituted aryl or heteroaryl having 4 to 20 ring atoms, or straightchain, branched or cyclic alkyl with 1 to 20, preferably 1 to 12 C atomswherein one or more non-adjacent CH₂ groups are optionally replaced, ineach case independently from one another, by —O—, —S—, —NR⁰—, —SiR⁰R⁰⁰—,—C(═O)—, —C(═O)O—, —CY¹═CY²— or —C≡C— in such a manner that O and/or Satoms are not linked directly to one another and which is unsubstitutedor substituted with one or more F or Cl atoms or OH groups, X⁰ ishalogen, preferably F, Cl or Br, and Y¹, Y², R⁰ and R⁰⁰ have themeanings given above and below.

Further preferably R¹ and/or R² in formula I denote aryl or heteroarylthat is substituted by one or more straight-chain, branched or cyclicalkyl groups with 1 to 30 C atoms, in which one or more non-adjacent CH₂groups are optionally replaced by one or more non-adjacent CH₂ groupsare optionally replaced by —O—, —S—, —C(O)—, —C(O)—O—, —O—C(O)—,—O—C(O)—O—, —NR⁰—, —SiR⁰R⁰⁰—, —CF₂—, —CHR⁰═CR⁰⁰—, —CY¹═CY²— or —C≡C— insuch a manner that O and/or S atoms are not linked directly to oneanother, and in which one or more H atoms are optionally replaced by F,Cl, Br, I or CN.

Preferred polymers according to the present invention comprise one ormore repeating units of formula II:—[(Ar¹)_(a)—(U)_(b)—(Ar²)_(c)—(Ar³)_(d)]—  IIwherein

-   U is a unit of formula I,-   Ar¹, Ar², Ar³ are, on each occurrence identically or differently,    and independently of each other, aryl or heteroaryl that is    different from U, preferably has 5 to 30 ring atoms, and is    optionally substituted, preferably by one or more groups R^(S),-   R^(S) is on each occurrence identically or differently F, Br, Cl,    —CN, —NC, —NCO, —NCS, —OCN, —SCN, —C(O)NR⁰R⁰⁰, —C(O)X⁰, —C(O)R⁰,    —C(O)OR⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H, —SO₂R⁰, —OH, —NO₂, —CF₃,    —SF₅, optionally substituted silyl, carbyl or hydrocarbyl with 1 to    40 C atoms that is optionally substituted and optionally comprises    one or more hetero atoms,-   R⁰ and R⁰⁰ are independently of each other H or optionally    substituted C₁₋₄₀ carbyl or hydrocarbyl, and preferably denote H or    alkyl with 1 to 12 C-atoms,-   X⁰ is halogen, preferably F, Cl or Br,-   a, b and c are on each occurrence identically or differently 0, 1 or    2,-   d is on each occurrence identically or differently 0 or an integer    from 1 to 10,    wherein the polymer comprises at least one repeating unit of formula    II wherein b is at least 1.

Further preferred polymers according to the present invention comprise,in addition to the units of formula I or II, one or more repeating unitsselected from monocyclic or polycyclic aryl or heteroaryl groups thatare optionally substituted.

These additional repeating units are preferably selected of formula III—[(Ar¹)_(a)-(A^(c))_(b)-(Ar²)_(c)—(Ar³)_(d)]—  IIIwherein Ar¹, Ar², Ar³, a, b, c and d are as defined in formula II, andA^(c) is an aryl or heteroaryl group that is different from U and Ar¹⁻³,preferably has 5 to 30 ring atoms, is optionally substituted by one ormore groups R^(S) as defined above and below, and is preferably selectedfrom aryl or heteroaryl groups having electron acceptor properties,wherein the polymer comprises at least one repeating unit of formula IIIwherein b is at least 1.

R^(s) preferably has one of the meanings given for R¹.

The conjugated polymers according to the present invention arepreferably selected of formula IV:*

(A)_(x)(B)_(y)

_(n)*  IVwherein

-   A is a unit of formula I or II or its preferred subformulae,-   B is a unit that is different from A and comprises one or more aryl    or heteroaryl groups that are optionally substituted, and is    preferably selected of formula III,-   x is >0 and ≦1,-   y is ≧0 and <1,-   x+y is 1, and-   n is an integer >1.

Preferred polymers of formula IV are selected of the following formulae*—[(Ar¹—U—Ar²)_(x)—(Ar³)_(y)]_(n)—*  IVa*—[(Ar¹—U—Ar²)_(x)—(Ar³—Ar³)_(y)]_(n)—*  IVb*—[(Ar¹—U—Ar²)_(x)—(Ar³—Ar³—Ar³)_(y)]_(n)—*  IVc*—[(Ar¹)_(a)—(U)_(b)—(Ar²)_(c)—(Ar³)_(d)]_(n)—*  IVd*—([(Ar¹)_(a)—(U)_(b)—(Ar²)_(c)—(Ar³)_(d)]_(x)—[(Ar¹)_(a)-(A^(c))_(b)-(Ar²)_(c)—(Ar³)_(d)]_(y))_(n)—  IVewherein U, Ar¹, Ar², Ar³, a, b, c and d have in each occurrenceidentically or differently one of the meanings given in formula II,A^(c) has on each occurrence identically or differently one of themeanings given in formula III, and x, y and n are as defined in formulaIV, wherein these polymers can be alternating or random copolymers, andwherein in formula IVd and IVe in at least one of the repeating units[(Ar¹)_(a)—(U)_(b)—(Ar²)_(c)—(Ar³)_(d)] and in at least one of therepeating units [(Ar¹)_(a)-(A^(c))_(b)-(Ar²)_(c)—(Ar³)_(d)] b is atleast 1.

In the polymers according to the present invention, the total number ofrepeating units n is preferably from 2 to 10,000. The total number ofrepeating units n is preferably ≧5, very preferably ≧10, most preferably≧50, and preferably ≦500, very preferably ≦1,000, most preferably≦2,000, including any combination of the aforementioned lower and upperlimits of n.

The polymers of the present invention include homopolymers andcopolymers, like statistical or random copolymers, alternatingcopolymers and block copolymers, as well as combinations thereof.

Especially preferred are polymers selected from the following groups:

-   -   Group A consisting of homopolymers of the unit U or (Ar¹—U) or        (Ar¹—U—Ar²) or (Ar¹—U—Ar³) or (U—Ar²—Ar³) or (Ar¹—U—Ar²—Ar³),        i.e. where all repeating units are identical,    -   Group B consisting of random or alternating copolymers formed by        identical units (Ar¹—U—Ar²) and identical units (Ar³),    -   Group C consisting of random or alternating copolymers formed by        identical units (Ar¹—U—Ar²) and identical units (A¹),    -   Group D consisting of random or alternating copolymers formed by        identical units (Ar¹—U—Ar²) and identical units (Ar¹-A^(c)-Ar²),        wherein in all these groups U, A^(c), Ar¹, Ar² and Ar³ are as        defined above and below, in groups A, B and C Ar¹, Ar² and Ar³        are different from a single bond, and in group D one of Ar¹ and        Ar² may also denote a single bond.

Preferred polymers of formula IV and IVa to IVe are selected of formulaVR⁵-chain-R⁶  Vwherein “chain” denotes a polymer chain of formulae IV or IVa to IVe,and R⁵ and R⁶ have independently of each other one of the meanings of R¹as defined above, or denote, independently of each other, H, F, Br, Cl,I, —CH₂Cl, —CHO, —CR′═CR″₂, —SiR′R″R′″, —SiR′X′X″, —SiR′R″X′,—SnR′R″R′″, —BR′R″, —B(OR′)(OR″), —B(OH)₂, —O—SO₂—R′, —C≡CH, —C≡C—SiR′₃,—ZnX′ or an endcap group, X′ and X″ denote halogen, R′, R″ and R′″ haveindependently of each other one of the meanings of R⁰ given in formulaI, and two of R′, R″ and R′″ may also form a ring together with thehetero atom to which they are attached.

Preferred endcap groups R⁵ and R⁶ are H, C₁₋₂₀ alkyl, or optionallysubstituted C₆₋₁₂ aryl or C₂₋₁₀ heteroaryl, very preferably H or phenyl.

In the polymers represented by formula IV, IVa to IVe and V, x denotesthe mole fraction of units A, y denotes the mole fraction of units B,and n denotes the degree of polymerisation or total number of units Aand B. These formulae includes block copolymers, random or statisticalcopolymers and alternating copolymers of A and B, as well ashomopolymers of A for the case when x is >0 and y is 0.

Another aspect of the invention relates to monomers of formula VIR⁷—(Ar¹)_(a)—U—(Ar²)_(b)—R⁸  VIwherein U, Ar¹, Ar², a and b have the meanings of formula II, or one ofthe preferred meanings as described above and below, and R⁷ and R⁸ are,preferably independently of each other, selected from the groupconsisting of Cl, Br, I, O-tosylate, O-triflate, O-mesylate,O-nonaflate, —SiMe₂F, —SiMeF₂, —O—SO₂Z¹, —B(OZ²)₂, —CZ³═C(Z³)₂, —C≡CH,—C≡CSi(Z¹)₃, —ZnX⁰ and —Sn(Z⁴)₃, wherein X⁰ is halogen, preferably Cl,Br or I, Z¹⁻⁴ are selected from the group consisting of alkyl and aryl,each being optionally substituted, and two groups Z² may also togetherform a cyclic group.

Especially preferred are monomers of the following formulaeR⁷—Ar¹—U—Ar²—R⁸  VI1R⁷—U—R⁸  VI2R⁷—Ar¹—U—R⁸  VI3R⁷—U—Ar²—R⁸  VI4wherein U, Ar¹, Ar², R⁷ and R⁸ are as defined in formula VI.

Especially preferred are repeating units, monomers and polymers offormulae I, II, III, IV, IVa-IVe, V, VI and their subformulae whereinone or more of Ar¹, Ar² and Ar³ denote aryl or heteroaryl, preferablyhaving electron donor properties, selected from the group consisting ofthe following formulae

wherein one of X¹¹ and X¹² is S and the other is Se, and R¹¹, R¹², R¹³,R¹⁴, R¹⁵, R¹⁶, R¹⁷ and R¹⁸ independently of each other denote H or haveone of the meanings of R¹ as defined above and below.

Further preferred are repeating units, monomers and polymers of formulaeI, II, III, IV, IVa to IVe, V, VI and their subformulae wherein A^(c)and/or Ar³ denotes aryl or heteroaryl, preferably having electronacceptor properties, selected from the group consisting of the followingformulae

wherein one of X¹¹ and X¹² is S and the other is Se, and R¹¹, R¹², R¹³,R¹⁴, R¹⁵ and R¹⁶ independently of each other denote H or have one of themeanings of R¹ as defined above and below.

Especially preferred copolymers of the following formulae:—(U)_(x)—  IVa—(U)_(x)—(Ar)_(x)—  IVb—(U—Ar)_(n)—  IVcwherein U and Ar¹ are as defined in formula II, and n, x and y are asdefined in formula IV.

Further preferred are repeating units, monomers and polymers of formulaeI-VI and their subformulae selected from the following list of preferredembodiments:

-   -   y is ≧0 and ≦1,    -   X¹ and X² are C(R¹R²),    -   X¹ and X² are C═(R¹R²),    -   X¹ and X² are Si(R¹R²),    -   X¹ and X² are C═O,    -   n is at least 5, preferably at least 10, very preferably at        least 50, and up to 2,000, preferably up to 500.    -   M_(w) is at least 5,000, preferably at least 8,000, very        preferably at least 10,000, and preferably up to 300,000, very        preferably up to 100,000,    -   one of R¹ and R² is H and the other is different from H,    -   R¹ and R² are different from H,    -   R¹ and/or R² are independently of each other selected from the        group consisting of primary alkyl with 1 to 30 C atoms,        secondary alkyl with 3 to 30 C atoms, and tertiary alkyl with 4        to 30 C atoms, wherein in all these groups one or more H atoms        are optionally replaced by F,    -   R¹ and/or R² are independently of each other selected from the        group consisting of aryl and heteroaryl, each of which is        optionally fluorinated, alkylated or alkoxylated and has 4 to 30        ring atoms,    -   R¹ and/or R² are independently of each other selected from the        group consisting of primary alkoxy or sulfanylalkyl with 1 to 30        C atoms, secondary alkoxy or sulfanylalkyl with 3 to 30 C atoms,        and tertiary alkoxy or sulfanylalkyl with 4 to 30 C atoms,        wherein in all these groups one or more H atoms are optionally        replaced by F,    -   R¹ and/or R² are independently of each other selected from the        group consisting of aryloxy and heteroaryloxy, each of which is        optionally alkylated or alkoxylated and has 4 to 30 ring atoms,    -   R¹ and/or R² are independently of each other selected from the        group consisting of alkylcarbonyl, alkoxycarbonyl and        alkylcarbonyloxy, all of which are straight-chain or branched,        are optionally fluorinated, and have from 1 to 30 C atoms,    -   R¹ and/or R² denote independently of each other F, Cl, Br, I,        CN, R⁹, —C(O)—R⁹, —C(O)—O—R⁹, or —O—C(O)—R⁹, —SO₂—R⁹, —SO₃—R⁹,        wherein R⁹ is straight-chain, branched or cyclic alkyl with 1 to        30 C atoms, in which one or more non-adjacent C atoms are        optionally replaced by —O—, —S—, —C(O)—, —C(O)—O—, —O—C(O)—,        —O—C(O)—O—, —SO₂—, —SO₃—, —CR⁰═CR⁰⁰— or —C≡C— and in which one        or more H atoms are optionally replaced by F, Cl, Br, I or CN,        or R⁹ is aryl or heteroaryl having 4 to 30 ring atoms which is        unsubstituted or which is substituted by one or more halogen        atoms or by one or more groups R¹ as defined above,    -   R⁰ and R⁰⁰ are selected from H or C₁-C₁₀-alkyl,    -   R⁵ and R⁶ are selected from H, halogen, —CH₂Cl, —CHO,        —CH═CH₂—SiR′R″R′″, —SnR′R″R′″, —BR′R″, —B(OR′)(OR″), —B(OH)₂,        P-Sp, C₁-C₂₀-alkyl, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyl,        C₁-C₂₀-fluoroalkyl and optionally substituted aryl or        heteroaryl, preferably phenyl,    -   R⁷ and R⁸ are, preferably independently of each other, selected        from the group consisting of Cl, Br, I, O-tosylate, O-triflate,        O-mesylate, O-nonaflate, —SiMe₂F, —SiMeF₂, —O—SO₂Z¹, —B(OZ²)₂,        —CZ³═C(Z⁴)₂, —C≡CH, C≡CSi(Z¹)₃, —ZnX⁰ and —Sn(Z⁴)₃, wherein X⁰        is halogen, Z¹⁻⁴ are selected from the group consisting of alkyl        and aryl, each being optionally substituted, and two groups Z²        may also form a cyclic group.

The compounds of the present invention can be synthesized according toor in analogy to methods that are known to the skilled person and aredescribed in the literature. Other methods of preparation can be takenfrom the examples. For example, the polymers can be suitably prepared byaryl-aryl coupling reactions, such as Yamamoto coupling, Suzukicoupling, Stille coupling, Sonogashira coupling, Heck coupling orBuchwald coupling. Suzuki coupling and Yamamoto coupling are especiallypreferred. The monomers which are polymerised to form the repeat unitsof the polymers can be prepared according to methods which are known tothe person skilled in the art.

Preferably the polymers are prepared from monomers of formula VI ortheir preferred subformulae as described above and below.

Another aspect of the invention is a process for preparing a polymer bycoupling one or more identical or different monomeric units of formula Ior monomers of formula VI with each other and/or with one or morecomonomers in a polymerisation reaction, preferably in an aryl-arylcoupling reaction.

Suitable and preferred comonomers are selected from the followingformulaeR⁷—(Ar¹)_(a)-A^(c)-(Ar²)_(c)—R⁸  CR⁷—Ar¹—R⁸  DR⁷—Ar³—R⁸  Ewherein Ar¹, Ar², Ar³, a and c have one of the meanings of formula II orone of the preferred meanings given above and below, A^(c) has one ofthe meanings of formula III or one of the preferred meanings given aboveand below, and R⁷ and R⁸ have one of meanings of formula VI or one ofthe preferred meanings given above and below.

Very preferred is a process for preparing a polymer by coupling one ormore monomers selected from formula VI or formulae VI1-VI4 with one ormore monomers of formula C, and optionally with one or more monomersselected from formula D and E, in an aryl-aryl coupling reaction,wherein preferably R⁷ and R⁸ are selected from Cl, Br, I, —B(OZ²)₂ and—Sn(Z⁴)₃.

For example, preferred embodiments of the present invention relate to

a) a process of preparing a polymer by coupling a monomer of formula VI1R⁷—Ar¹—U—Ar²—R⁸  VI1with a monomer of formula D1R⁷—Ar¹—R⁸  D1in an aryl-aryl coupling reaction,orb) a process of preparing a polymer by coupling a monomer of formula VI2R⁷—U—R⁸  VI2with a monomer of formula C1R⁷—Ar¹-A^(c)-Ar²—R⁸  C1in an aryl-aryl coupling reaction,orc) a process of preparing a polymer by coupling a monomer of formula VI2R⁷—U—R⁸  VI2with a monomer of formula C2R⁷-A^(c)-R⁸  C2in an aryl-aryl coupling reaction, ord) a process of preparing a polymer by coupling a monomer of formula VI2R⁷—U—R⁸  VI2with a monomer of formula C2R⁷-A^(c)-R⁸  C1and a monomer of formula D1R⁷—Ar¹—R⁸  D1in an aryl-aryl coupling reaction,wherein R⁷, R⁸, U, A^(c), Ar^(1,2) are as defined in formula II, III andVI, and R⁷ and R⁸ are preferably selected from Cl, Br, I, —B(OZ²)₂ and—Sn(Z⁴)₃ as defined in formula VI.

Preferred aryl-aryl coupling methods used in the processes describedabove and below are Yamamoto coupling, Kumada coupling, Negishicoupling, Suzuki coupling, Stille coupling, Sonogashira coupling, Heckcoupling, C—H activation coupling, Ullmann coupling or Buchwaldcoupling. Especially preferred are Suzuki coupling, Negishi coupling,Stille coupling and Yamamoto coupling. Suzuki coupling is described forexample in WO 00/53656 A1. Negishi coupling is described for example inJ. Chem. Soc., Chem. Commun., 1977, 683-684. Yamamoto coupling isdescribed in for example in T. Yamamoto et al., Prog. Polym. Sci., 1993,17, 1153-1205, or WO 2004/022626 A1. For example, when using Yamamotocoupling, monomers having two reactive halide groups are preferablyused. When using Suzuki coupling, monomers having two reactive boronicacid or boronic acid ester groups or two reactive halide groups arepreferably used. When using Stille coupling, monomers having tworeactive stannane groups or two reactive halide groups are preferablyused. When using Negishi coupling, monomers having two reactiveorganozinc groups or two reactive halide groups are preferably used.

Suzuki and Stille polymerisation may be used to prepare homopolymers aswell as statistical, alternating and block random copolymers.Statistical or block copolymers can be prepared for example from theabove monomers wherein one of the reactive groups is halogen and theother reactive group is a boronic acid, boronic acid derivative group orand alkylstannane. The synthesis of statistical, alternating and blockcopolymers is described in detail for example in WO 03/048225 A2 or WO2005/014688 A2.

Preferred catalysts, especially for Suzuki, Negishi or Stille coupling,are selected from Pd(0) complexes or Pd(II) salts. Preferred Pd(0)complexes are those bearing at least one phosphine ligand such asPd(Ph₃P)₄. Another preferred phosphine ligand istris(ortho-tolyl)phosphine, i.e. Pd(o-ToI₃P)₄. Preferred Pd(II) saltsinclude palladium acetate, i.e. Pd(OAc)₂. Alternatively the Pd(0)complex can be prepared by mixing a Pd(0) dibenzylideneacetone complex,for example tris(dibenzyl-ideneacetone)dipalladium(0),bis(dibenzylideneacetone)palladium(0), or Pd(II) salts e.g. palladiumacetate, with a phosphine ligand, for example triphenylphosphine,tris(ortho-tolyl)phosphine or tri(tert-butyl)phosphine. Suzuki couplingis performed in the presence of a base, for example sodium carbonate,potassium carbonate, lithium hydroxide, potassium phosphate or anorganic base such as tetraethylammonium carbonate or tetraethylammoniumhydroxide. Yamamoto coupling employs a Ni(0) complex, for examplebis(1,5-cyclooctadienyl) nickel(0).

As alternatives to halogens as described above, leaving groups offormula —O—SO₂Z¹ can be used wherein Z¹ is as described above.Particular examples of such leaving groups are tosylate, mesylate andtriflate.

Especially suitable and preferred synthesis methods of the repeatingunits, monomers and polymers of formulae I-VI and their subformulae areillustrated in the synthesis schemes shown hereinafter, wherein R^(1,2)have the meanings given above.

The synthesis of two bromo benzothiophene isomers is exemplarily shownin Scheme 1.

The synthesis of indacenodibenzothiophenes is exemplarily shown inSchemes 2 to 5.

The synthesis of dithia-dicyclopenta-dibenzothiophenes is exemplarilyshown in Schemes 6 and 7.

The homopolymerisation of the indacenodibenzothiophenes is exemplarilyshown in Scheme 8.

wherein X¹, X², A¹, A² and B are as defined in formula I, and eitherY¹═Br and Y²═(B(OR)₂, or Y¹═Br and Y²═SnR₃.

The co-polymerisation of the indacenodibenzothiophenes is exemplarilyshown in Scheme 9

The novel methods of preparing monomers and polymers as described aboveand below are another aspect of the invention.

The compounds and polymers according to the present invention can alsobe used in mixtures or polymer blends, for example together withmonomeric compounds or together with other polymers havingcharge-transport, semiconducting, electrically conducting,photoconducting and/or light emitting semiconducting properties, or forexample with polymers having hole blocking or electron blockingproperties for use as interlayers or charge blocking layers in OLEDdevices. Thus, another aspect of the invention relates to a polymerblend comprising one or more polymers according to the present inventionand one or more further polymers having one or more of theabove-mentioned properties. These blends can be prepared by conventionalmethods that are described in prior art and known to the skilled person.Typically the polymers are mixed with each other or dissolved insuitable solvents and the solutions combined.

Another aspect of the invention relates to a formulation comprising oneor more small molecules, polymers, mixtures or polymer blends asdescribed above and below and one or more organic solvents.

Preferred solvents are aliphatic hydrocarbons, chlorinated hydrocarbons,aromatic hydrocarbons, ketones, ethers and mixtures thereof. Additionalsolvents which can be used include 1,2,4-trimethylbenzene,1,2,3,4-tetramethyl benzene, pentylbenzene, mesitylene, cumene, cymene,cyclohexylbenzene, diethylbenzene, tetralin, decalin, 2,6-lutidine,2-fluoro-m-xylene, 3-fluoro-o-xylene, 2-chlorobenzotrifluoride,N,N-dimethylformamide, 2-chloro-6-fluorotoluene, 2-fluoroanisole,anisole, 2,3-dimethylpyrazine, 4-fluoroanisole, 3-fluoroanisole,3-trifluoro-methylanisole, 2-methylanisole, phenetol, 4-methylanisole,3-methylanisole, 4-fluoro-3-methylanisole, 2-fluorobenzonitrile,4-fluoroveratrol, 2,6-dimethylanisole, 3-fluorobenzo-nitrile,2,5-dimethylanisole, 2,4-dimethylanisole, benzonitrile,3,5-dimethylanisole, N,N-dimethylaniline, ethyl benzoate,1-fluoro-3,5-dimethoxy-benzene, 1-methylnaphthalene,N-methylpyrrolidinone, 3-fluorobenzotrifluoride, benzotrifluoride,dioxane, trifluoromethoxy-benzene, 4-fluorobenzotrifluoride,3-fluoropyridine, toluene, 2-fluoro-toluene, 2-fluorobenzotrifluoride,3-fluorotoluene, 4-isopropylbiphenyl, phenyl ether, pyridine,4-fluorotoluene, 2,5-difluorotoluene, 1-chloro-2,4-difluorobenzene,2-fluoropyridine, 3-chlorofluorobenzene, 1-chloro-2,5-difluorobenzene,4-chlorofluorobenzene, chloro-benzene, o-dichlorobenzene,2-chlorofluorobenzene, p-xylene, m-xylene, o-xylene or mixture of o-,m-, and p-isomers. Solvents with relatively low polarity are generallypreferred. For inkjet printing solvents and solvent mixtures with highboiling temperatures are preferred. For spin coating alkylated benzeneslike xylene and toluene are preferred.

Examples of especially preferred solvents include, without limitation,dichloromethane, trichloromethane, chlorobenzene, o-dichlorobenzene,tetrahydrofuran, anisole, morpholine, toluene, o-xylene, m-xylene,p-xylene, 1,4-dioxane, acetone, methylethylketone, 1,2-dichloroethane,1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, ethyl acetate, n-butylacetate, N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide,tetraline, decaline, indane, methyl benzoate, ethyl benzoate, mesityleneand/or mixtures thereof.

The concentration of the compounds or polymers in the solution ispreferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight.Optionally, the solution also comprises one or more binders to adjustthe rheological properties, as described for example in WO 2005/055248A1.

After the appropriate mixing and ageing, solutions are evaluated as oneof the following categories: complete solution, borderline solution orinsoluble. The contour line is drawn to outline the solubilityparameter-hydrogen bonding limits dividing solubility and insolubility.‘Complete’ solvents falling within the solubility area can be chosenfrom literature values such as published in “Crowley, J. D., Teague, G.S. Jr and Lowe, J. W. Jr., Journal of Paint Technology, 1966, 38 (496),296”. Solvent blends may also be used and can be identified as describedin “Solvents, W. H. Ellis, Federation of Societies for CoatingsTechnology, p 9-10, 1986”. Such a procedure may lead to a blend of ‘non’solvents that will dissolve both the polymers of the present invention,although it is desirable to have at least one true solvent in a blend.

The compounds and polymers according to the present invention can alsobe used in patterned OSC layers in the devices as described above andbelow. For applications in modern microelectronics it is generallydesirable to generate small structures or patterns to reduce cost (moredevices/unit area), and power consumption. Patterning of thin layerscomprising a polymer according to the present invention can be carriedout for example by photolithography, electron beam lithography or laserpatterning.

For use as thin layers in electronic or electrooptical devices thecompounds, polymers, polymer blends or formulations of the presentinvention may be deposited by any suitable method. Liquid coating ofdevices is more desirable than vacuum deposition techniques. Solutiondeposition methods are especially preferred. The formulations of thepresent invention enable the use of a number of liquid coatingtechniques. Preferred deposition techniques include, without limitation,dip coating, spin coating, ink jet printing, nozzle printing,letter-press printing, screen printing, gravure printing, doctor bladecoating, roller printing, reverse-roller printing, offset lithographyprinting, dry offset lithography printing, flexographic printing, webprinting, spray coating, curtain coating, brush coating, slot dyecoating or pad printing.

Ink jet printing is particularly preferred when high resolution layersand devices needs to be prepared. Selected formulations of the presentinvention may be applied to prefabricated device substrates by ink jetprinting or microdispensing. Preferably industrial piezoelectric printheads such as but not limited to those supplied by Aprion, Hitachi-Koki,InkJet Technology, On Target Technology, Picojet, Spectra, Trident, Xaarmay be used to apply the organic semiconductor layer to a substrate.Additionally semi-industrial heads such as those manufactured byBrother, Epson, Konica, Seiko Instruments Toshiba TEC or single nozzlemicrodispensers such as those produced by Microdrop and Microfab may beused.

In order to be applied by ink jet printing or microdispensing, thecompounds or polymers should be first dissolved in a suitable solvent.Solvents must fulfil the requirements stated above and must not have anydetrimental effect on the chosen print head. Additionally, solventsshould have boiling points >100° C., preferably >140° C. and morepreferably >150° C. in order to prevent operability problems caused bythe solution drying out inside the print head. Apart from the solventsmentioned above, suitable solvents include substituted andnon-substituted xylene derivatives, di-C₁₋₂-alkyl formamide, substitutedand non-substituted anisoles and other phenol-ether derivatives,substituted heterocycles such as substituted pyridines, pyrazines,pyrimidines, pyrrolidinones, substituted and non-substitutedN,N-di-C₁₋₂-alkylanilines and other fluorinated or chlorinatedaromatics.

A preferred solvent for depositing a compound or polymer according tothe present invention by ink jet printing comprises a benzene derivativewhich has a benzene ring substituted by one or more substituents whereinthe total number of carbon atoms among the one or more substituents isat least three. For example, the benzene derivative may be substitutedwith a propyl group or three methyl groups, in either case there beingat least three carbon atoms in total. Such a solvent enables an ink jetfluid to be formed comprising the solvent with the compound or polymer,which reduces or prevents clogging of the jets and separation of thecomponents during spraying. The solvent(s) may include those selectedfrom the following list of examples: dodecylbenzene,1-methyl-4-tert-butylbenzene, terpineol, limonene, isodurene,terpinolene, cymene, diethylbenzene. The solvent may be a solventmixture, that is a combination of two or more solvents, each solventpreferably having a boiling point >100° C., more preferably >140° C.Such solvent(s) also enhance film formation in the layer deposited andreduce defects in the layer.

The ink jet fluid (that is mixture of solvent, binder and semiconductingcompound) preferably has a viscosity at 20° C. of 1-100 mPa·s, morepreferably 1-50 mPa·s and most preferably 1-30 mPa·s.

The polymer blends and formulations according to the present inventioncan additionally comprise one or more further components or additivesselected for example from surface-active compounds, lubricating agents,wetting agents, dispersing agents, hydrophobing agents, adhesive agents,flow improvers, defoaming agents, deaerators, diluents which may bereactive or non-reactive, auxiliaries, nanoparticles, colourants, dyesor pigments, furthermore, especially in case crosslinkable binders areused, catalysts, sensitizers, stabilizers, inhibitors, chain-transferagents or co-reacting monomers.

The compounds and polymers to the present invention are useful as chargetransport, semiconducting, electrically conducting, photoconducting orlight emitting materials in optical, electrooptical, electronic,electroluminescent or photoluminescent components or devices. In thesedevices, the polymers of the present invention are typically applied asthin layers or films.

Thus, the present invention also provides the use of the semiconductingcompound, polymer, polymers blend, formulation or layer in an electronicdevice. The formulation may be used as a high mobility semiconductingmaterial in various devices and apparatus. The formulation may be used,for example, in the form of a semiconducting layer or film. Accordingly,in another aspect, the present invention provides a semiconducting layerfor use in an electronic device, the layer comprising a compound,polymer, polymer blend or formulation according to the invention. Thelayer or film may be less than about 30 microns. For various electronicdevice applications, the thickness may be less than about 1 micronthick. The layer may be deposited, for example on a part of anelectronic device, by any of the aforementioned solution coating orprinting techniques.

The invention additionally provides an electronic device comprising acompound, polymer, polymer blend, formulation or organic semiconductinglayer according to the present invention. Especially preferred devicesare OFETs, TFTs, ICs, logic circuits, capacitors, RFID tags, OLEDs,OLETs, OPEDs, OPVs, OPDs, solar cells, laser diodes, photoconductors,photodetectors, electrophotographic devices, electrophotographicrecording devices, organic memory devices, sensor devices, chargeinjection layers, Schottky diodes, planarising layers, antistatic films,conducting substrates and conducting patterns.

Especially preferred electronic device are OFETs, OLEDs and OPV devices,in particular bulk heterojunction (BHJ) OPV devices and OPD devices. Inan OFET, for example, the active semiconductor channel between the drainand source may comprise the layer of the invention. As another example,in an OLED device, the charge (hole or electron) injection or transportlayer may comprise the layer of the invention.

For use in OPV or OPD devices the polymer according to the presentinvention is preferably used in a formulation that comprises orcontains, more preferably consists essentially of, very preferablyexclusively of, a p-type (electron donor) semiconductor and an n-type(electron acceptor) semiconductor. The p-type semiconductor isconstituted by a polymer according to the present invention. The n-typesemiconductor can be an inorganic material such as zinc oxide (ZnO_(x)),zinc tin oxide (ZTO), titan oxide (TiO_(x)), molybdenum oxide (MoO_(x)),nickel oxide (NiO_(x)), or cadmium selenide (CdSe), or an organicmaterial such as graphene or a fullerene or substituted fullerene, forexample an indene-C₆₀-fullerene bisaduct like ICBA, or a(6,6)-phenyl-butyric acid methyl ester derivatized methano C₆₀fullerene, also known as “PCBM-C₆₀” or “C₆₀PCBM”, as disclosed forexample in G. Yu, J. Gao, J. C. Hummelen, F. Wudl, A. J. Heeger, Science1995, Vol. 270, p. 1789 ff and having the structure shown below, orstructural analogous compounds with e.g. a C₆₁ fullerene group, a C₇₀fullerene group, or a C₇₁ fullerene group, or an organic polymer (seefor example Coakley, K. M. and McGehee, M. D. Chem. Mater. 2004, 16,4533).

Preferably the polymer according to the present invention is blendedwith an n-type semiconductor such as a fullerene or substitutedfullerene, like for example PCBM-C₆₀, PCBM-C₇₀, PCBM-C₆₁, PCBM-C₇₁,bis-PCBM-C₆₁, bis-PCBM-C₇₁, ICBA(1′,1″,4′,4″-tetrahydro-di[1,4]methanonaphthaleno[1,2:2′,3′;56,60:2″,3″][5,6]fullerene-C60-Ih),graphene, or a metal oxide, like for example, ZnO_(x), TiO_(x), ZTO,MoO_(x), NiO_(x), to form the active layer in an OPV or OPD device. Thedevice preferably further comprises a first transparent orsemi-transparent electrode on a transparent or semi-transparentsubstrate on one side of the active layer, and a second metallic orsemi-transparent electrode on the other side of the active layer.

Further preferably the OPV or OPD device comprises, between the activelayer and the first or second electrode, one or more additional bufferlayers acting as hole transporting layer and/or electron blocking layer,which comprise a material such as metal oxide, like for example, ZTO,MoO_(x), NiO_(x), a conjugated polymer electrolyte, like for examplePEDOT:PSS, a conjugated polymer, like for example polytriarylamine(PTAA), an organic compound, like for exampleN,N′-diphenyl-N,N′-bis(1-naphthyl)(1,1′-biphenyl)-4,4′diamine (NPB),N,N′-diphenyl-N,N′-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD), oralternatively as hole blocking layer and/or electron transporting layer,which comprise a material such as metal oxide, like for example,ZnO_(x), TiO_(x), a salt, like for example LiF, NaF, CsF, a conjugatedpolymer electrolyte, like for examplepoly[3-(6-trimethylammoniumhexyl)thiophene],poly(9,9-bis(2-ethylhexyl)-fluorene]-b-poly[3-(6-trimethylammoniumhexyl)thiophene],orpoly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9dioctylfluorene)] or an organic compound, like for exampletris(8-quinolinolato)-aluminium(III) (Alq₃),4,7-diphenyl-1,10-phenanthroline.

In a blend or mixture of a polymer according to the present inventionwith a fullerene or modified fullerene, the ratio polymer:fullerene ispreferably from 5:1 to 1:5 by weight, more preferably from 1:1 to 1:3 byweight, most preferably 1:1 to 1:2 by weight. A polymeric binder mayalso be included, from 5 to 95% by weight. Examples of binder includepolystyrene (PS), polypropylene (PP) and polymethylmethacrylate (PMMA).

To produce thin layers in BHJ OPV devices the compounds, polymers,polymer blends or formulations of the present invention may be depositedby any suitable method. Liquid coating of devices is more desirable thanvacuum deposition techniques. Solution deposition methods are especiallypreferred. The formulations of the present invention enable the use of anumber of liquid coating techniques. Preferred deposition techniquesinclude, without limitation, dip coating, spin coating, ink jetprinting, nozzle printing, letter-press printing, screen printing,gravure printing, doctor blade coating, roller printing, reverse-rollerprinting, offset lithography printing, dry offset lithography printing,flexographic printing, web printing, spray coating, dip coating, curtaincoating, brush coating, slot dye coating or pad printing. For thefabrication of OPV devices and modules area printing method compatiblewith flexible substrates are preferred, for example slot dye coating,spray coating and the like.

Suitable solutions or formulations containing the blend or mixture of apolymer according to the present invention with a C₆₀ or C₇₀ fullereneor modified fullerene like PCBM must be prepared. In the preparation offormulations, suitable solvent must be selected to ensure fulldissolution of both component, p-type and n-type and take into accountthe boundary conditions (for example rheological properties) introducedby the chosen printing method.

Organic solvent are generally used for this purpose. Typical solventscan be aromatic solvents, halogenated solvents or chlorinated solvents,including chlorinated aromatic solvents. Examples include, but are notlimited to chlorobenzene, 1,2-dichlorobenzene, chloroform,1,2-dichloroethane, dichloromethane, carbon tetrachloride, toluene,cyclohexanone, ethylacetate, tetrahydrofuran, anisole, morpholine,o-xylene, m-xylene, p-xylene, 1,4-dioxane, acetone, methylethylketone,1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane,ethyl acetate, n-butyl acetate, dimethylformamide, dimethylacetamide,dimethylsulfoxide, tetraline, decaline, indane, methyl benzoate, ethylbenzoate, mesitylene and combinations thereof.

The OPV device can for example be of any type known from the literature(see e.g. Waldauf et al., Appl. Phys. Lett., 2006, 89, 233517).

A first preferred OPV device according to the invention comprises thefollowing layers (in the sequence from bottom to top):

-   -   optionally a substrate,    -   a high work function electrode, preferably comprising a metal        oxide, like for example ITO, serving as anode,    -   an optional conducting polymer layer or hole transport layer,        preferably comprising an organic polymer or polymer blend, for        example of PEDOT:PSS (poly(3,4-ethylenedioxythiophene):        poly(styrene-sulfonate), or TBD        (N,N′-dyphenyl-N—N′-bis(3-methylphenyl)-1,1′biphenyl-4,4′-diamine)        or NBD        (N,N′-dyphenyl-N—N′-bis(1-napthylphenyl)-1,1′biphenyl-4,4′-diamine),    -   a layer, also referred to as “active layer”, comprising a p-type        and an n-type organic semiconductor, which can exist for example        as a p-type/n-type bilayer or as distinct p-type and n-type        layers, or as blend or p-type and n-type semiconductor, forming        a BHJ,    -   optionally a layer having electron transport properties, for        example comprising LiF,    -   a low work function electrode, preferably comprising a metal        like for example aluminum, serving as cathode,    -   wherein at least one of the electrodes, preferably the anode, is        transparent to visible light, and    -   wherein the p-type semiconductor is a polymer according to the        present invention.

A second preferred OPV device according to the invention is an invertedOPV device and comprises the following layers (in the sequence frombottom to top):

-   -   optionally a substrate,    -   a high work function metal or metal oxide electrode, comprising        for example ITO, serving as cathode,    -   a layer having hole blocking properties, preferably comprising a        metal oxide like TiO_(x) or Zn_(x),    -   an active layer comprising a p-type and an n-type organic        semiconductor, situated between the electrodes, which can exist        for example as a p-type/n-type bilayer or as distinct p-type and        n-type layers, or as blend or p-type and n-type semiconductor,        forming a BHJ,    -   an optional conducting polymer layer or hole transport layer,        preferably comprising an organic polymer or polymer blend, for        example of PEDOT:PSS or TBD or NBD,    -   an electrode comprising a high work function metal like for        example silver, serving as anode,    -   wherein at least one of the electrodes, preferably the cathode,        is transparent to visible light, and    -   wherein the p-type semiconductor is a polymer according to the        present invention.

In the OPV devices of the present invention the p-type and n-typesemiconductor materials are preferably selected from the materials, likethe polymer/fullerene systems, as described above.

When the active layer is deposited on the substrate, it forms a BHJ thatphase separates at nanoscale level. For discussion on nanoscale phaseseparation see Dennler et al, Proceedings of the IEEE, 2005, 93 (8),1429 or Hoppe et al, Adv. Func. Mater, 2004, 14(10), 1005. An optionalannealing step may be then necessary to optimize blend morphology andconsequently OPV device performance.

Another method to optimize device performance is to prepare formulationsfor the fabrication of OPV(BHJ) devices that may include high boilingpoint additives to promote phase separation in the right way.1,8-Octanedithiol, 1,8-diiodooctane, nitrobenzene, chloronaphthalene,and other additives have been used to obtain high-efficiency solarcells. Examples are disclosed in J. Peet, et al, Nat. Mater., 2007, 6,497 or Fréchet et al. J. Am. Chem. Soc., 2010, 132, 7595-7597.

The compounds, polymers, formulations and layers of the presentinvention are also suitable for use in an OFET as the semiconductingchannel. Accordingly, the invention also provides an OFET comprising agate electrode, an insulating (or gate insulator) layer, a sourceelectrode, a drain electrode and an organic semiconducting channelconnecting the source and drain electrodes, wherein the organicsemiconducting channel comprises a compound, polymer, polymer blend,formulation or organic semiconducting layer according to the presentinvention. Other features of the OFET are well known to those skilled inthe art.

OFETs where an OSC material is arranged as a thin film between a gatedielectric and a drain and a source electrode, are generally known, andare described for example in U.S. Pat. No. 5,892,244, U.S. Pat. No.5,998,804, U.S. Pat. No. 6,723,394 and in the references cited in thebackground section. Due to the advantages, like low cost productionusing the solubility properties of the compounds according to theinvention and thus the processibility of large surfaces, preferredapplications of these FETs are such as integrated circuitry, TFTdisplays and security applications.

The gate, source and drain electrodes and the insulating andsemiconducting layer in the OFET device may be arranged in any sequence,provided that the source and drain electrode are separated from the gateelectrode by the insulating layer, the gate electrode and thesemiconductor layer both contact the insulating layer, and the sourceelectrode and the drain electrode both contact the semiconducting layer.

An OFET device according to the present invention preferably comprises:

-   -   a source electrode,    -   a drain electrode,    -   a gate electrode,    -   a semiconducting layer,    -   one or more gate insulator layers,    -   optionally a substrate.        wherein the semiconductor layer preferably comprises a compound,        polymer, polymer blend or formulation as described above and        below.

The OFET device can be a top gate device or a bottom gate device.Suitable structures and manufacturing methods of an OFET device areknown to the skilled in the art and are described in the literature, forexample in US 2007/0102696 A1.

The gate insulator layer preferably comprises a fluoropolymer, like e.g.the commercially available Cytop 809M® or Cytop 107M® (from AsahiGlass). Preferably the gate insulator layer is deposited, e.g. byspin-coating, doctor blading, wire bar coating, spray or dip coating orother known methods, from a formulation comprising an insulator materialand one or more solvents with one or more fluoro atoms (fluorosolvents),preferably a perfluorosolvent. A suitable perfluorosolvent is e.g. FC75®(available from Acros, catalogue number 12380). Other suitablefluoropolymers and fluorosolvents are known in prior art, like forexample the perfluoropolymers Teflon AF® 1600 or 2400 (from DuPont) orFluoropel® (from Cytonix) or the perfluorosolvent FC 43® (Acros, No.12377). Especially preferred are organic dielectric materials having alow permittivity (or dielectric constant) from 1.0 to 5.0, verypreferably from 1.8 to 4.0 (“low k materials”), as disclosed for examplein US 2007/0102696 A1 or U.S. Pat. No. 7,095,044.

In security applications, OFETs and other devices with semiconductingmaterials according to the present invention, like transistors ordiodes, can be used for RFID tags or security markings to authenticateand prevent counterfeiting of documents of value like banknotes, creditcards or ID cards, national ID documents, licenses or any product withmonetry value, like stamps, tickets, shares, cheques etc.

Alternatively, the materials according to the invention can be used inOLEDs, e.g. as the active display material in a flat panel displayapplications, or as backlight of a flat panel display like e.g. a liquidcrystal display. Common OLEDs are realized using multilayer structures.An emission layer is generally sandwiched between one or moreelectron-transport and/or hole-transport layers. By applying an electricvoltage electrons and holes as charge carriers move towards the emissionlayer where their recombination leads to the excitation and henceluminescence of the lumophor units contained in the emission layer. Theinventive compounds, materials and films may be employed in one or moreof the charge transport layers and/or in the emission layer,corresponding to their electrical and/or optical properties. Furthermoretheir use within the emission layer is especially advantageous, if thecompounds, materials and films according to the invention showelectroluminescent properties themselves or comprise electroluminescentgroups or compounds. The selection, characterization as well as theprocessing of suitable monomeric, oligomeric and polymeric compounds ormaterials for the use in OLEDs is generally known by a person skilled inthe art, see, e.g., Willer et al, Synth. Metals, 2000, 111-112, 31-34,Alcala, J. Appl. Phys., 2000, 88, 7124-7128 and the literature citedtherein.

According to another use, the materials according to this invention,especially those showing photoluminescent properties, may be employed asmaterials of light sources, e.g. in display devices, as described in EP0 889 350 A1 or by C. Weder et al., Science, 1998, 279, 835-837.

A further aspect of the invention relates to both the oxidised andreduced form of the compounds according to this invention. Either lossor gain of electrons results in formation of a highly delocalised ionicform, which is of high conductivity. This can occur on exposure tocommon dopants. Suitable dopants and methods of doping are known tothose skilled in the art, e.g. from EP 0 528 662, U.S. Pat. No.5,198,153 or WO 96/21659.

The doping process typically implies treatment of the semiconductormaterial with an oxidating or reducing agent in a redox reaction to formdelocalised ionic centres in the material, with the correspondingcounterions derived from the applied dopants. Suitable doping methodscomprise for example exposure to a doping vapor in the atmosphericpressure or at a reduced pressure, electrochemical doping in a solutioncontaining a dopant, bringing a dopant into contact with thesemiconductor material to be thermally diffused, and ion-implantation ofthe dopant into the semiconductor material.

When electrons are used as carriers, suitable dopants are for examplehalogens (e.g., I₂, Cl₂, Br₂, ICl, ICl₃, IBr and IF), Lewis acids (e.g.,PF₅, AsF₅, SbF₅, BF₃, BCl₃, SbCl₅, BBr₃ and SO₃), protonic acids,organic acids, or amino acids (e.g., HF, HCl, HNO₃, H₂SO₄, HClO₄, FSO₃Hand ClSO₃H), transition metal compounds (e.g., FeCl₃, FeOCl, Fe(ClO₄)₃,Fe(4-CH₃C₆H₄SO₃)₃, TiCl₄, ZrCl₄, HfCl₄, NbF₅, NbCl₅, TaCl₅, MoF₅, MoCl₅,WF₅, WCl₆, UF₆ and LnCl₃ (wherein Ln is a lanthanoid), anions (e.g.,Cl⁻, Br⁻, I⁻, I₃ ⁻, HSO₄ ⁻, SO₄ ²⁻, NO₃ ⁻, ClO₄ ⁻, BF₄ ⁻, PF₆ ⁻, AsF₆ ⁻,SbF₆ ⁻, FeCl₄ ⁻, Fe(CN)₆ ³⁻, and anions of various sulfonic acids, suchas aryl-SO₃ ⁻). When holes are used as carriers, examples of dopants arecations (e.g., H⁺, Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺), alkali metals (e.g., Li,Na, K, Rb, and Cs), alkaline-earth metals (e.g., Ca, Sr, and Ba), O₂,XeOF₄, (NO₂ ⁺)(SbF₆ ⁻), (NO₂ ⁺)(SbCl₆ ⁻), (NO₂ ⁺)(BF₄ ⁻), AgClO₄,H₂IrCl₆, La(NO₃)₃.6H₂O, FSO₂OOSO₂F, Eu, acetylcholine, R₄N⁺, (R is analkyl group), R₄P⁺ (R is an alkyl group), R₆As⁺ (R is an alkyl group),and R₃S⁺ (R is an alkyl group).

The conducting form of the compounds of the present invention can beused as an organic “metal” in applications including, but not limitedto, charge injection layers and ITO planarising layers in OLEDapplications, films for flat panel displays and touch screens,antistatic films, printed conductive substrates, patterns or tracts inelectronic applications such as printed circuit boards and condensers.

The compounds and formulations according to the present invention mayalso be suitable for use in organic plasmon-emitting diodes (OPEDs), asdescribed for example in Koller et al., Nat. Photonics, 2008, 2, 684.

According to another use, the materials according to the presentinvention can be used alone or together with other materials in or asalignment layers in LCD or OLED devices, as described for example in US2003/0021913. The use of charge transport compounds according to thepresent invention can increase the electrical conductivity of thealignment layer. When used in an LCD, this increased electricalconductivity can reduce adverse residual dc effects in the switchableLCD cell and suppress image sticking or, for example in ferroelectricLCDs, reduce the residual charge produced by the switching of thespontaneous polarisation charge of the ferroelectric LCs. When used inan OLED device comprising a light emitting material provided onto thealignment layer, this increased electrical conductivity can enhance theelectroluminescence of the light emitting material. The compounds ormaterials according to the present invention having mesogenic or liquidcrystalline properties can form oriented anisotropic films as describedabove, which are especially useful as alignment layers to induce orenhance alignment in a liquid crystal medium provided onto saidanisotropic film. The materials according to the present invention mayalso be combined with photoisomerisable compounds and/or chromophoresfor use in or as photoalignment layers, as described in US 2003/0021913A1.

According to another use the materials according to the presentinvention, especially their water-soluble derivatives (for example withpolar or ionic side groups) or ionically doped forms, can be employed aschemical sensors or materials for detecting and discriminating DNAsequences. Such uses are described for example in L. Chen, D. W.McBranch, H. Wang, R. Helgeson, F. Wudl and D. G. Whitten, Proc. Natl.Acad. Sci. U.S.A., 1999, 96, 12287; D. Wang, X. Gong, P. S. Heeger, F.Rininsland, G. C. Bazan and A. J. Heeger, Proc. Natl. Acad. Sci. U.S.A.,2002, 99, 49; N. DiCesare, M. R. Pinot, K. S. Schanze and J. R.Lakowicz, Langmuir, 2002, 18, 7785; D. T. McQuade, A. E. Pullen, T. M.Swager, Chem. Rev., 2000, 100, 2537.

Unless the context clearly indicates otherwise, as used herein pluralforms of the terms herein are to be construed as including the singularform and vice versa.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, mean “including but not limited to”, andare not intended to (and do not) exclude other components.

It will be appreciated that variations to the foregoing embodiments ofthe invention can be made while still falling within the scope of theinvention. Each feature disclosed in this specification, unless statedotherwise, may be replaced by alternative features serving the same,equivalent or similar purpose. Thus, unless stated otherwise, eachfeature disclosed is one example only of a generic series of equivalentor similar features.

All of the features disclosed in this specification may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. In particular, thepreferred features of the invention are applicable to all aspects of theinvention and may be used in any combination. Likewise, featuresdescribed in non-essential combinations may be used separately (not incombination).

Above and below, unless stated otherwise percentages are percent byweight and temperatures are given in degrees Celsius. The values of thedielectric constant c (“permittivity”) refer to values taken at 20° C.and 1,000 Hz.

The invention will now be described in more detail by reference to thefollowing examples, which are illustrative only and do not limit thescope of the invention.

Example 1 (3-Bromophenyl)-(2,2-dimethoxyethyl)sulfane

To a solution of 2-bromo-1,1-dimethoxy-ethane (49.2 g, 0.29 mol) and3-bromo-benzenethiol (50.0 g, 0.26 mol) in dimethyl sulfoxide (400 cm³)is added a solution of potassium hydroxide (18.0 g, 0.32 mol) in water(40 cm³). The resulting solution is stirred at 23° C. for 17 hours. Thereaction mixture is extracted with 40-60 petroleum (5×100 cm³) and thecombined organic layer is washed with brine (2×100 cm³), dried overanhydrous magnesium sulphate and filtered. The filtrate is concentratedin vacuo to obtain (3-Bromophenyl)-(2,2-dimethoxyethyl)sulfane (65.0 g,89%) as a colourless oil. MS (m/e): 278 (M+, 100%). ¹H NMR (300 MHz,CDCl₃) 7.52-7.50 (1H, m, ArH), 7.33-7.27 (2H, m, ArH), 7.15 (1H, dd,ArH, J 7.2, 7.2), 4.53 (1H, t, CH, J 5.6), 3.38 (6H, s, CH₃), 3.12 (2H,d, CH₂, J 5.6).

4-Bromobenzo[b]thiophene and 6-bromobenzo[b]thiophene

To a mixture chlorobenzene (500 cm³) and polyphosphoric acid (150 cm³)is added (3-Bromophenyl)-(2,2-dimethoxyethyl)sulfane (60.0 g, 0.22 mol).The resulting reaction mixture is stirred at 130° C. for 1 hour. Thereaction mixture is then cooled to 23° C. and concentrated in vacuo. Thecrude product is purified using silica gel column chromatography(n-heptane) to give 4-bromobenzo[b]thiophene (11.2 g, 14%) as a whitecrystalline solid [MS (m/e): 214 (M+, 100%). ¹H NMR (300 MHz, CDCl₃)7.81 (1H, d, ArH, J 8.0), 7.55-7.47 (3H, m, ArH), 7.20 (1H, dd, ArH, J7.9, 7.9)] and 6-bromobenzo[b]thiophene (11.0 g, 24%) as a whitecrystalline solid. MS (m/e): 214 (M+, 99.0%). ¹H NMR (300 MHz, CDCl₃)8.00-8.03 (1H, m, ArH), 7.68 (1H, d, ArH, J 8.5), 7.47 (1H, dd, ArH, J1.8, 8.5), 7.42 (1H, d, ArH, J 5.5), 7.29 (1H, dd, ArH, J 5.5, 0.7).

(6-bromobenzo[b]thiophen-2-yl)trimethylsilane

Lithium diisopropylamide (2.0 M in THF, 31.0 cm³, 62 mmol) is addeddropwise to a solution of 6-bromo-benzo[b]thiophene (12.0 g, 56 mmol) inanhydrous tetrahydrofuran (150 cm³) under a nitrogen atmosphere at −30°C. over 30 minutes. The resulting solution is stirred at −20° C. for 2hours and then quenched with chlorotrimethylsilane (6.7 g, 62 mmol). Theice bath is removed and the reaction mixture is warmed to 23° C. andstirred for 17 hours. The reaction mixture is diluted with water (75cm³) and extracted with diethyl ether (5×50 cm³). The combined organiclayer is washed with brine (50 cm³) and dried over anhydrous magnesiumsulfate, filtered and the solvent removed in vacuo. The crude product ispurified using silica gel column chromatography (40-60 petroleum) togive (6-bromobenzo[b]thiophen-2-yl)trimethylsilane (8.9 g, 55%). MS(m/e): 286 (M+, 96.5%). ¹H NMR (300 MHz, CDCl₃) 8.01 (1H, s, ArH), 7.65(1H, d, ArH, J 8.4), 7.45-7.41 (1H, dd, ArH, J 1.8, 8.4), 7.40 (1H, s,ArH), 0.37 (9H, s, CH₃).

Trimethyl(6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzo[b]thiophen-2-yl)silane

Nitrogen gas is bubbled through a suspension of(6-bromo-benzo[b]thiophen-2-yl)-trimethylsilane (2.0 g, 7.0 mmol),bis(pinacolato)diboron (2.1 g, 8.4 mmol),[1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium (II) (1.0 g, 1.3mmol) and potassium acetate (4.1 g, 42 mmol) in anhydrous 1,4-dioxane(50 cm³) for 1 hour. The reaction mixture is heated at 100° C. for 17hours, allowed to cool to 23° C., diluted with diethyl ether (300 cm³)and filtered. The filtrate is concentrated in vacuo and the crudeproduct purified using silica gel column chromatography (40-60petroleum) to givetrimethyl(6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzo[b]thiophen-2-yl)silane(2.1 g 87%) as a cream solid. MS (m/e): 332 (M+, 96.5%). ¹H NMR (300MHz, CDCl₃) 8.36 (1H, s, ArH), 7.80 (1H, d, ArH, J 8.0), 7.73 (1H, d,ArH, J 8.0), 7.46 (1H, s, ArH), 1.37 (12H, s, CH₃), 0.38 (9H, s, CH₃).

2,5-Bis-(2-trimethylsilanyl-benzo[b]thiophen-6-yl)-terephthalic aciddiethyl ester

Nitrogen gas is bubbled through a solution of 2,5-dibromo-terephthalicacid diethyl ester (4.0 g, 11 mmol) andtrimethyl(6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzo[b]thiophen-2-yl)silane(7.7 g, 23 mmol) in anhydrous toluene (40 cm³) for 1 hour. Potassiumcarbonate (6.1 g, 44 mmol) and tetrakis(triphenylphosphine)palladium(0)(0.6 g, 0.5 mmol) are then added to the reaction mixture. Afteraddition, the reaction mixture is stirred at 120° C. for 17 hours. Thereaction mixture is concentrated in vacuo and purified using silica gelcolumn chromatography (gradient of 40-60 petroleum to diethyl ether) togive 2,5-bis-(2-trimethylsilanyl-benzo[b]thiophen-6-yl)-terephthalicacid diethyl ester (3.5 g 53%) as a white solid. ¹H NMR (300 MHz, CDCl₃)8.05 (2H, s, ArH), 7.95 (2H, d, ArH, J 8.0), 7.49-7.44 (4H, m, ArH),7.36 (1H, s, ArH), 3.93 (4H, q, CH₂, J 7.16), 0.72 (6H, t, CH₃, J 7.1),0.38 (18H, s, CH₃).

2,20-Trimethylsilanyl-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)

To a solution of 1-bromo-4-dodecyl-benzene (3.4 g, 10 mmol) in anhydroustetrahydrofuran (60 cm³) under a nitrogen atmosphere at −78° C. is addedt-butyllithium (1.9 M in heptanes, 10.9 cm³, 21.0 mmol) dropwise over 30minutes followed by stirring for one hour. A solution of2,5-bis-(2-trimethylsilanyl-benzo[b]thiophen-6-yl)-terephthalic aciddiethyl ester (1.6 g, 2.5 mmol) in anhydrous tetrahydrofuran (20 cm³) isadded in one portion followed by stirring at 23° C. for 17 hours. Thereaction mixture is then quenched with water (100 cm³), extracted withdiethyl ether (3×75 cm³). The combined organic layer is washed withwater (50 cm³), brine (50 cm³), dried over anhydrous magnesium sulphateand then filtered. The filtrate is concentrated in vacuo, trituratedwith methanol (50 cm³) and the solid collected by filtration to givecrude[4-[bis-(4-dodecyl-phenyl)-hydroxy-methyl]-2,5-bis-(2-trimethylsilanyl-benzo[b]thiophen-6-yl)-phenyl]-bis-(4-dodecyl-phenyl)-methanol.To a degassed suspension of amberlyst 15 (2.0 g) and anhydrous toluene(50 cm³) at 23° C. is added the crude[4-[bis-(4-dodecyl-phenyl)-hydroxy-methyl]-2,5-bis-(2-trimethylsilanyl-benzo[b]thiophen-6-yl)-phenyl]-bis-(4-dodecyl-phenyl)-methanol.The resulting suspension is stirred at 23° C. for 17 hours under anitrogen atmosphere. The resulting suspension is filtered and washedthrough with dichloromethane (100 cm³). The filtrate is concentrated invacuo and the crude is purified using silica gel column chromatography(40-60 petroleum) to give2,20-trimethylsilanyl-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)(380 mg, 10%) as a pale cream solid. ¹H NMR (300 MHz, CDCl₃) 7.82 (2H,s, ArH), 7.79 (2H, d, ArH, J 8.1), 7.72 (2H, d, ArH, J 8.1), 7.46 (2H,s, ArH), 7.21 (8H, d, ArH, J 8.3), 7.05 (8H, d, ArH, J 8.3), 2.57-2.52(8H, m, CH₂), 1.65-1.49 (8H, m, CH₂), 1.38-1.15 (72H, m, CH₂), 0.87(12H, t, CH₃, J 6.5), 0.30 (18H, s, CH₃).

2,20-Dibromo-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)

1-Bromo-pyrrolidine-2,5-dione (84.5 mg, 0.48 mmol) is added portion wiseto a solution of2,20-trimethylsilanyl-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)(300 mg, 0.24 mmol) in anhydrous tetrahydrofuran (20 cm³) under anitrogen atmosphere with absence of light at 0° C. After addition, thereaction mixture is stirred at 23° C. for 17 hours. The reaction mixtureis concentrated in vacuo and the crude product is recrystallized fromacetone:methyl ethyl ketone (20 cm³, 1:1) to give2,20-dibromo-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)(200 mg, 66%) as a white crystalline solid. ¹H NMR (300 MHz, CDCl₃) 7.80(2H, s, ArH), 7.71 (2H, d, ArH, J 8.2), 7.66 (2H, d, ArH, J 8.2), 7.32(2H, s, ArH), 7.15 (8H, d, ArH, J 8.4), 7.06 (8H, d, ArH, J 8.4),2.57-2.52 (8H, m, CH₂), 1.61-1.50 (8H, m, CH₂), 1.39-1.16 (72H, m, CH₂),0.87 (12H, t, CH₃, J 6.6).

Poly[2,20-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)]-alt-[2,2′bithiophene](Polymer 1)

Nitrogen gas is bubbled through a mixture of2,20-dibromo-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)(200 mg, 0.133 mmol) and 5,5′-bis-trimethylstannanyl-[2,2′]bithiophenyl(65.5 mg, 0.133 mmol) in anhydrous toluene (2 cm³) and anhydrousN,N-dimethylformamide (0.5 cm³) for 1 hour.Tris(dibenzylideneacetone)dipalladium(0) (4.9 mg, 0.005 mmol) andtri-o-tolyl-phosphine (6.5 mg, 0.02 mmol) are added to the reactionmixture followed by heating at 120° C. for 65 hours. The reactionmixture is poured into methanol (100 cm³) and the polymer precipitatecollected by filtration. The crude polymer is subjected to sequentialSoxhlet extraction; methanol, acetone, 40-60 petroleum, 80-100petroleum, cyclohexanes, chloroform and chlorobenzene. The chlorobenzeneextract is poured into methanol (200 cm³) and the polymer precipitatecollected by filtration to givepoly[2,20-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)]-alt-[2,2′bithiophene](150 mg, 75%) as a dark red solid. GPC (chlorobenzene, 50° C.)M_(n)=65,900 g/mol, M_(w)=183,400 g/mol. GPC (1,2,4-trichlorobenzene,140° C.) M_(n)=62,600 g/mol, M_(w)=128,700 g/mol.

Poly[2,20-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)]-alt-[2,7-(9,10-dioctyl-phenanthrene)](Polymer 2)

Nitrogen gas is bubbled through a mixture of2,7-di([1,3,2]dioxaborolane)-9,10-dioctyl-phenanthrene (65.1 mg, 0.120mmol),2,20-dibromo-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)(180 mg, 0.120 mmol) and potassium phosphate monohydrate (0.2 g, 1.1mmol) in a mixture of toluene (3 cm³), 1,4-dioxane (3 cm³) and water (3cm³) for 1 hour. Tris(dibenzylideneacetone)dipalladium(0) (2.7 mg, 0.003mmol) and tri-o-tolyl-phosphine (5.8 mg, 0.019 mmol) are added to thereaction mixture followed by heating at 100° C. for 3 hours. Thereaction mixture is poured into methanol (100 cm³) and the polymerprecipitate collected by filtration. The crude polymer is subjected tosequential Soxhlet extraction; methanol, acetone, 40-60 petroleum,80-100 petroleum, cyclohexanes and chloroform. The chloroform extract ispoured into methanol (150 cm³) and the polymer precipitate collected byfiltration to givepoly[2,20-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-1,7-dithia-dicyclopenta[a,h]-indeno[1,2-b]fluorene)]-alt-[2,7-(9,10-dioctyl-phenanthrene)](170 mg 81%) as a black solid. GPC (1,2,4-trichlorobenzene, 140° C.)M_(n)=15,200 g/mol, M_(w)=26,100 g/mol.

Example 2 Diethyl 2,5-di(benzo[b]thiophen-4-yl)terephthalate

To a mixture of magnesium turnings (0.91 g, 36 mmol) and anhydroustetrahydrofuran (20 cm³) is added 4-bromobenzo[b]thiophene (7.0 g, 33mmol) and the mixture heated at 75° C. for 17 hours. The resultingsuspension is syringed into a solution of tributyltinchloride (16 g, 49mmol) in anhydrous tetrahydrofuran (20 cm³) at −78° C. The ice bath isremoved and the resulting mixture is stirred at 23° C. for 17 hours. Thereaction mixture is quenched with water (100 cm³) and extracted with40-60 petroleum (5×50 cm³). The combined organic phase is washed withbrine (50 cm³), dried over magnesium sulphate, filtered and the solventremoved in vacuo to give crude(4-tributylstannanyl-benzo[b]thiophen-2-yl). Nitrogen gas is bubbled foran hour through a suspension of 2,5-dibromo-terephthalic acid diethylester (2.3 g, 6.0 mmol) in anhydrous N,N-dimethylformamide (50 cm³) andtris(dibenzylideneacetone)dipalladium(0) (0.3 g, 0.3 mmol) andtri(o-tolyl)phosphine (0.2 g, 0.6 mmol) are added. The resulting mixtureis heated to 90° C. and the prepared(4-tributylstannanyl-benzo[b]thiophen-2-yl) is added. The reactionmixture is stirred at 90° C. for 17 hours. The reaction mixture isconcentrated in vacuo and purified using silica gel columnchromatography (gradient of 40-60 petroleum to diethyl ether) to givediethyl 2,5-di(benzo[b]thiophen-4-yl)terephthalate (0.9 g, 31%) as awhite solid. ¹H NMR (300 MHz, CDCl₃) 8.05 (2H, s, ArH), 7.95 (2H, d,ArH, J 8.0), 7.49-7.44 (4H, m, ArH), 7.37 (2H, d, ArH, J 5.5), 7.28 (2H,d, ArH, J 5.5), 3.92 (4H, q, CH₂, J 7.2), 0.72 (6H, t, 2CH₃, J 7.2).

6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-3,9-dithia-dicyclopenta[c,f]-indeno[1,2-b]fluorine

To a solution of 1-bromo-4-dodecyl-benzene (1.8 g, 5.5 mmol) inanhydrous tetrahydrofuran (100 cm³) under a nitrogen atmosphere at −78°C. is added t-butyllithium (1.7 M in heptane, 6.5 cm³, 11 mmol) dropwiseover 30 minutes followed by stirring for 1 hour.2,5-Bis-benzo[b]thiophen-4-yl-terephthalic acid diethyl ester (0.54 g,1.1 mmol) is added in one portion followed by stirring at 23° C. for 17hours. The reaction mixture is then quenched with water (125 cm³) andextracted with diethyl ether (3×50 cm³). The combined organic layer iswashed with water (50 cm³), brine (50 cm³), dried over anhydrousmagnesium sulphate and then filtered. The filtrate is concentrated invacuo, triturated with methanol (50 cm³) and the solid collected byfiltration to give crude{2,5-bis-benzo[b]thiophen-6-yl-4-[hydroxy-bis-(4-dodecyl-phenyl)-methyl]-phenyl}-bis-(4-octyl-phenyl)-methanol.To a suspension of toluene-4-sulfonic acid (2.1 g, 12 mmol) in anhydrousdichloromethane (100 cm³) under a nitrogen atmosphere is added{2,5-bis-benzo[b]thiophen-6-yl-4-[hydroxy-bis-(4-dodecyl-phenyl)-methyl]-phenyl}-bis-(4-octyl-phenyl)-methanolin one portion. The resulting suspension is stirred at 23° C. for 17hours under a nitrogen atmosphere. The reaction mixture is concentratedin vacuo and purified using silica gel chromatography (gradient of 40-60petroleum to dichloromethane) to yield6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-3,9-dithia-dicyclopenta[c,f]indeno[1,2-b]fluorene(760 mg, 51%) as a white solid. ¹H NMR (300 MHz, CDCl₃) 8.13 (2H, s,ArH), 7.90 (2H, d, ArH, J 5.5), 7.89 (2H, d, ArH, J 8.0), 7.62 (2H, d,ArH, J 5.5), 7.44 (2H, d, ArH, J 8.0), 7.25 (8H, d, ArH, J 8.3), 7.08(8H, d, ArH, J 8.3), 2.59-2.53 (8H, m, CH₂), 1.66-1.55 (8H, m, CH₂),1.38-1.20 (72H, m, CH₂), 0.89 (12H, t, CH₃, J 7.5).

2,18-Dibromo-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-3,9-dithia-dicyclopenta[c,f]indeno[1,2-b]fluorene)

1-Bromo-pyrrolidine-2,5-dione (147 mg, 0.82 mmol) is added portion wiseto a solution of6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-3,9-dithia-dicyclopenta[c,f]indeno[1,2-b]fluorene(500 mg, 0.37 mmol) in chloroform (50 cm³) and acetic acid (20 cm³)under a nitrogen atmosphere with absence of light at 0° C. Afteraddition, the reaction mixture is stirred at 23° C. for 17 hours. Thereaction mixture is concentrated in vacuo and the crude productcrystallized from n-heptane and diethyl ether (40 cm³, 1:1) to give2,18-dibromo-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-3,9-dithia-dicyclopenta[c,f]indeno[1,2-b]fluorene)(98 mg 18%) as a white crystalline solid. ¹H NMR (300 MHz, CDCl₃) 8.03(2H, s, ArH), 7.94 (2H, d, ArH, J 5.5), 7.65 (2H, d, ArH, J 5.5), 7.54(2H, s, ArH), 7.20 (8H, d, ArH, J 8.3), 7.08 (8H, d, ArH, J 8.3),2.57-2.52 (8H, m, CH₂), 1.63-1.53 (8H, m, CH₂), 1.32-1.16 (72H, m, CH₂),0.87 (12H, t, CH₃, J 7.5).

Poly[2,18-[(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-3,9-dithia-dicyclopenta[c,f]indeno[1,2-b]fluorene)]]-alt-[2,5-thieno[3,2-b]thiophene](Polymer 3)

Nitrogen gas is bubbled through a mixture of2,18-dibromo-(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-3,9-dithia-dicyclopenta[c,f]indeno[1,2-b]fluorene)(200.0 mg, 0.133 mmol), 5,5′-bis-trimethylstannanyl-[2,2′]bithiophenyl(62.0 mg, 0.133 mmol), tris(dibenzylideneacetone)dipalladium(0) (1.9 mg,0.003 mmol), tri-o-tolyl-phosphine (3.2 mg, 0.01 mmol) and anhydroustoluene (6 cm³) for 1 hour. The reaction mixture is then heated in apre-heated oil bath at 100° C. for 15 minutes. Bromobenzene (0.03 cm³)is added and the mixture heated at 100° C. for 10 minutes.Tributyl-phenyl-stannane (0.13 cm³) is then added and the mixture heatedat 100° C. for 20 minutes. The mixture allowed to cool slightly andpoured into stirred methanol (100 cm³) and the solid collected byfiltration. The crude polymer is subjected to sequential Soxhletextraction; acetone, 40-60 petrol, cyclohexane and chloroform. Thechloroform extract is concentrated in vacuo and poured into methanol(300 cm³) and the solid collected by filtration to givepoly[2,18-[(6,12-dihydro-6,6,12,12-tetrakis(4-dodecylphenyl)-3,9-dithia-dicyclopenta[c,f]indeno[1,2-b]fluorene)]]-alt-[2,5-thieno[3,2-b]thiophene](180 mg, 83%) as a dark red solid. GPC (chlorobenzene, 50° C.)M_(n)=29,000 g/mol, M_(w)=54,000 g/mol.

Example 3 Transistor Fabrication and Measurement

Top-gate thin-film organic field-effect transistors (OFETs) werefabricated on glass substrates with photolithographically defined Ausource-drain electrodes. A 7 mg/cm³ solution of the organicsemiconductor in dichlorobenzene was spin-coated on top followed by aspin-coated fluoropolymer dielectric material (Lisicon® D139 from Merck,Germany). Finally a photolithographically defined Au gate electrode wasdeposited. The electrical characterization of the transistor devices wascarried out in ambient air atmosphere using computer controlled Agilent4155C Semiconductor Parameter Analyser. Charge carrier mobility in thesaturation regime (μ_(sat)) was calculated for the. Field-effectmobility was calculated in the saturation regime (V_(d)>(V_(g)—V₀))using equation (1):

$\begin{matrix}{\left( \frac{\mathbb{d}I_{d}^{sat}}{\mathbb{d}V_{g}} \right)_{V_{d}} = {\frac{{WC}_{i}}{L}{\mu^{sat}\left( {V_{g} - V_{0}} \right)}}} & (1)\end{matrix}$where W is the channel width, L the channel length, C, the capacitanceof insulating layer, V_(g) the gate voltage, V₀ the turn-on voltage, andμ_(sat) is the charge carrier mobility in the saturation regime. Turn-onvoltage (V₀) was determined as the onset of source-drain current.

The mobility (μ_(sat)) for example polymer 1 in top-gate OFETs is 0.06cm²/Vs.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows the transfer characteristics and the charge carriermobility of a top-gate OFET prepared as described above, wherein polymer1 is used as the organic semiconductor.

The invention claimed is:
 1. A polymer comprising one or more units offormula I

wherein * in formula I indicates the position of chemical linkage to anadjacent unit of the polymer or to a terminal group of the polymer, X¹and X² independently of each other denote C(R¹R²), C═C(R¹R²), Si(R¹R²)or C═O, A¹ is

wherein the thiophene ring may also be substituted in 3-position by agroup R¹, * on the left side of the formulae for A¹ indicates theposition of chemical linkage to an adjacent unit of the polymer or to aterminal group of the polymer and the two * connected by a bond on theright side cyclic group of the formulae for A¹ indicates the position ofchemical linkage in the structure of formula I, A² is

wherein the thiophene ring may also be substituted in 3-position by agroup R¹, * on the right side of the formulae for A² indicates theposition of chemical linkage to an adjacent unit of the polymer or to aterminal group of the polymer and the two * connected by a bond on theleft side cyclic group of the formulae for A² indicates the position ofchemical linkage to the structure of formula I, B is

where the two * connected by a bond on each of the left and right sideof the cyclic group of the formulae for B indicates the position ofchemical linkage to the structure of formula I, R¹ and R² independentlyof each other denote H, straight-chain, branched or cyclic alkyl with 1to 30 C atoms, in which one or more non-adjacent CH₂ groups areoptionally replaced by —O—, —S—, —C(O)—, —C(S)—, —C(O)—O—, —O—C(O)—,—NR⁰—, —SiR⁰R⁰⁰—, —CF₂—, —CHR⁰═CR⁰⁰—, —CY¹═CY²— or —C≡C— in such amanner that O and/or S atoms are not linked directly to one another, andin which one or more H atoms are optionally replaced by F, Cl, Br, I orCN, or denote aryl, heteroaryl, aryloxy or heteroaryloxy with 4 to 20ring atoms which is optionally substituted, Y¹ and Y² independently ofeach other denote H, F, Cl or CN, R⁰ and R⁰⁰ independently of each otherdenote H or optionally substituted C₁₋₄₀ carbyl or hydrocarbyl.
 2. Thepolymer according to claim 1, characterized in that in formula I X¹ andX² denote C(R¹R²) or C═(R¹R²).
 3. The polymer according to claim 1,characterized in that the units of formula I are selected from thefollowing formulae:

wherein the * in each formula indicates the position of chemical linkageto an adjacent unit of the polymer or to a terminal group of thepolymer.
 4. The polymer according to claim 1, characterized in that itcomprises one or more units of formula II—[(Ar¹)_(a)—(U)_(b)—(Ar²)_(c)—(Ar³)_(d)]—  II wherein U is a unit offormula I as defined in claim 1, Ar¹, Ar², Ar³ are, on each occurrenceidentically or differently, and independently of each other, aryl orheteroaryl that is different from U, has 5 to 30 ring atoms and isoptionally substituted by one or more groups R^(S), R^(S) is on eachoccurrence identically or differently F, Br, Cl, —CN, —NC, —NCO, —NCS,—OCN, —SCN, —C(O)NR⁰R⁰⁰, —C(O)X⁰, —C(O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰,—SO₃H, —SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, optionally substituted silyl,carbyl or hydrocarbyl with 1 to 40 C atoms that is optionallysubstituted and optionally comprises one or more hetero atoms, R⁰ andR⁰⁰ are independently of each other H or optionally substituted C₁₋₄₀carbyl or hydrocarbyl, X⁰ is halogen, a, b, c are on each occurrenceidentically or differently 0, 1 or 2, d is on each occurrenceidentically or differently 0 or an integer from 1 to 10, wherein thepolymer comprises at least one repeating unit of formula II wherein b isat least
 1. 5. The polymer according to claim 4, characterized in thatit additionally comprises one or more repeating units selected offormula III—[(Ar¹)_(a)-(A^(c))_(b)-(Ar²)_(c)—(Ar³)_(d)]—  III wherein A^(c) is anaryl or heteroaryl group that is different from U and Ar¹⁻³, has 5 to 30ring atoms, is optionally substituted by one or more groups R^(S), andis selected from aryl or heteroaryl groups having electron acceptorproperties, wherein the polymer comprises at least one repeating unit offormula III wherein b is at least
 1. 6. The polymer according to claim1, characterized in that it is of formula IV:*

(A)_(x)(B)_(y)

_(n)*  IV wherein * in formula IV indicates the position of chemicallinkage to an adjacent unit of the polymer or to a terminal group of thepolymer, A is a unit of formula I as defined in claim 1, B is a unitthat is different from A and comprises one or more aryl or heteroarylgroups that are optionally substituted, x is >0 and ≦1, y is ≧0 and <1,x+y is 1, and n is an integer >1.
 7. The polymer according to claim 4,characterized in that it is selected from the following formulae*—[(Ar¹—U—Ar²)_(x)—(Ar³)_(y)]_(n)—*  IVa*—[(Ar¹—U—Ar²)_(x)—(Ar³—Ar³)_(y)]_(n)—*  IVb*—[(Ar¹—U—Ar²)_(x)—(Ar³—Ar³—Ar³)_(y)]_(n)—*  IVc*—[(Ar¹)_(a)—(U)_(b)—(Ar²)_(c)—(Ar³)_(d)]_(n)—*  IVd*—([(Ar¹)_(a)—(U)_(b)—(Ar²)_(c)—(Ar³)_(d)]_(x)—[(Ar¹)_(a)-(A^(c))_(b)-(Ar²)_(c)—(Ar³)_(d)]_(y))_(n)—  IVewherein * in each formula indicates the position of chemical linkage toan adjacent unit of the polymer or to a terminal group of the polymer,A^(c) is an aryl or heteroaryl group that is different from U and Ar¹⁻³,has 5 to 30 ring atoms, is optionally substituted by one or more groupsR^(S), and is selected from aryl or heteroaryl groups having electronacceptor properties and x, y and n, x is >0 and ≦1, y is ≧0 and <1, x+yis 1, and n is an integer >1, wherein these polymers can be alternatingor random copolymers, and wherein in formula IVd and IVe in at least oneof the repeating units [(Ar¹)_(a)—(U)_(b)—(Ar²)_(c)—(Ar³)_(d)] and in atleast one of the repeating units[(Ar¹)_(a)-(A^(c))_(b)-(Ar²)_(c)—(Ar³)_(d)] b is at least
 1. 8. Thepolymer according to claim 6, characterized in that it is of formula VR⁵-chain-R⁶  V wherein “chain” is a polymer chain of formulae IV, R⁵ andR⁶ have independently of each other one of the meanings of R¹, ordenote, independently of each other, H, F, Br, Cl, I, —CH₂Cl, —CHO,—CR′═CR″₂, —SiR′R″R′″, —SiR′X′X″, —SiR′R″X′, —SnR′R″R′″, —BR′R″,—B(OR′)(OR″), —B(OH)₂, —O—SO₂—R′, —C≡CH, —C≡C—SiR′₃, —ZnX′, or an endcapgroup, wherein X′ and X″ denote halogen, R′, R″ and R″ haveindependently of each other one of the meanings of R⁰, and two of R′, R″and R′″ may also form a ring together with the hetero atom to which theyare attached.
 9. The polymer according to claim 4, wherein one or moreof Ar¹, Ar² and Ar³ denote aryl or heteroaryl selected from the groupconsisting of the following formulae

wherein * in each formula indicates the positions of the two chemicallinkages of the Ar¹, Ar² or Ar³ groups to their adjacent groups, one ofX¹¹ and X¹² is S and the other is Se, and R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶,R¹⁷ and R¹⁸ independently of each other denote H or have one of themeanings of R¹.
 10. The polymer according to claim 5, wherein A^(c)and/or Ar³ denotes aryl or heteroaryl selected from the group consistingof the following formulae

wherein * in each formula indicates the positions of the two chemicallinkages of the Ac or Ar¹ groups to their adjacent groups, one of X¹¹and X¹² is S and the other is Se, and R¹¹, R¹², R¹³, R¹⁴, R¹⁵ and R¹⁶independently of each other denote H or have one of the meanings of R¹.11. A mixture or polymer blend comprising one or more polymers accordingto claim 1 and one or more compounds or polymers having semiconducting,charge transport, hole/electron transport, hole/electron blocking,electrically conducting, photoconducting or light emitting properties.12. The mixture or polymer blend according to claim 11, characterized inthat it further comprises one or more n-type organic semiconductorcompounds.
 13. The mixture or polymer blend according to claim 12,characterized in that the n-type organic semiconductor compound is afullerene or substituted fullerene.
 14. A formulation comprising one ormore polymers according to claim 1, and one or more solvents.
 15. Anoptical, electrooptical, electronic, electroluminescent orphotoluminescent device, or a component thereof, or an assemblycomprising it, which comprises a mixture or polymer blend according toclaim
 11. 16. A charge transport, semiconducting, electricallyconducting, photoconducting or light emitting material comprising apolymer blend according to claim
 1. 17. An optical, electrooptical,electronic, electroluminescent or photoluminescent device, or acomponent thereof, or an assembly comprising it, which comprises acharge transport, semiconducting, electrically conducting,photoconducting or light emitting material, and comprises a polymeraccording to claim
 1. 18. A device, a component thereof, or an assemblycomprising it, according to claim 17, wherein the device is selectedfrom organic field effect transistors (OFET), thin film transistors(TFT), organic light emitting diodes (OLED), organic light emittingtransistors (OLET), organic photovoltaic devices (OPV), organicphotodetectors (OPD), organic solar cells, laser diodes, Schottkydiodes, and photoconductors, the component is selected from chargeinjection layers, charge transport layers, interlayers, planarisinglayers, antistatic films, polymer electrolyte membranes (PEM),conducting substrates, conducting patterns, and the assembly is selectedfrom integrated circuits (IC), radio frequency identification (RFID)tags or security markings or security devices containing them, flatpanel displays or backlights thereof, electrophotographic devices,electrophotographic recording devices, organic memory devices, sensordevices, biosensors and biochips.
 19. The device according to claim 18,which is an OFET, bulk heterojunction (BHJ) OPV device or inverted BHJOPV device.
 20. A monomer of formula VIR⁷—(Ar¹)_(a)—U—(Ar²)_(c)—R⁸  VI wherein a and c are on each occurrenceidentically or differently 0, 1 or 2, U is a unit of formula I,

wherein * in formula I indicates the position of chemical linkage to anadjacent unit of the polymer or to a terminal group of the polymer, X¹and X² independently of each other denote C(R¹R²), C═C(R¹R²), Si(R¹R²)or C═O, A¹ is

wherein the thiophene ring may also be substituted in 3-position by agroup R¹, * on the left side of the formulae for A¹ indicates theposition of chemical linkage to an adjacent unit of the polymer or to aterminal group of the polymer and the two * connected by a bond on theright side cyclic group of the formulae for A¹ indicates the position ofchemical linkage to the structure of formula I, A² is

wherein the thiophene ring may also be substituted in 3-position by agroup R¹, * on the right side of the formulae for A² indicates theposition of chemical linkage to an adjacent unit of the polymer or to aterminal group of the polymer and the two * connected by a bond on theleft side cyclic group of the formulae for A² indicates the position ofchemical linkage to the structure of formula I, B is

where the two * connected by a bond on each of the left and right sideof the cyclic group of the formulae for B indicates the position ofchemical linkage to the structure of formula I, R¹ and R² independentlyof each other denote H, straight-chain, branched or cyclic alkyl with 1to 30 C atoms, in which one or more non-adjacent CH₂ groups areoptionally replaced by —O—, —S—, —C(O)—, —C(S)—, —C(O)—O—, —O—C(O)—,—NR⁰—, —SiR⁰R⁰⁰—, —CF₂—, —CHR⁰═CR⁰⁰—, —CY¹═CY²— or —C≡C— in such amanner that O and/or S atoms are not linked directly to one another, andin which one or more H atoms are optionally replaced by F, Cl, Br, I orCN, or denote aryl, heteroaryl, aryloxy or heteroaryloxy with 4 to 20ring atoms which is optionally substituted, Y¹ and Y² independently ofeach other denote H, F, Cl or CN, R⁰ and R⁰⁰ independently of each otherdenote H or optionally substituted C₁₋₄₀ carbyl or hydrocarbyl, Ar¹ andAr² are, on each occurrence identically or differently, andindependently of each other, aryl or heteroaryl that is different fromU, has 5 to 30 ring atoms and is optionally substituted, by one or moregroups R^(S), and R⁷ and R⁸ are selected from the group consisting ofCl, Br, I, O-tosylate, O-triflate, O-mesylate, O-nonaflate, —SiMe₂F,—SiMeF₂, —O—SO₂Z¹, —B(OZ²)₂, —CZ³═C(Z³)₂, —C≡CH, —C≡CSi(Z¹)₃, —ZnX⁰ and—Sn(Z⁴)₃, wherein X⁰ is halogen, Z¹⁻⁴ are selected from the groupconsisting of alkyl and aryl, each being optionally substituted, and twogroups Z² may also together form a cyclic group.
 21. The monomeraccording to claim 20, which is selected from the following formulaeR⁷—Ar¹—U—Ar²—R⁸  VI1R⁷—U—R⁸  VI2R⁷—Ar¹—U—R⁸  VI3R⁷—U—Ar²—R⁸  VI4.
 22. A process of preparing a polymer according toclaim 1, which comprises: coupling one or more monomers of formula VI:R⁷—(Ar¹)_(a)—U—(Ar²)_(c)—R⁸  VI wherein a and c are on each occurrenceidentically or differently 0, 1 or 2, Ar¹, and Ar² are, on eachoccurrence identically or differently, and independently of each other,aryl or heteroaryl that is different from U, has 5 to 30 ring atoms andis optionally substituted by one or more groups R^(S), wherein R⁷ and R⁸are selected from Cl, Br, I, —B(OZ²)₂ and —Sn(Z⁴)₃, with each otherand/or with one or more monomers selected from the following formulaeR⁷—(Ar¹)_(a)-A^(c)-(Ar²)_(c)—R⁸  CR⁷—Ar¹—R⁸  DR⁷—Ar³—R⁸  E wherein, A^(c) is an aryl or heteroaryl group that isdifferent from U and Ar³ has 5 to 30 ring atoms, is optionallysubstituted by one or more groups R^(S), and is selected from aryl orheteroaryl groups having electron acceptor properties, and R⁷ and R⁸ areselected from Cl, Br, I, —B(OZ²)₂ and —Sn(Z⁴)₃, in an aryl-aryl couplingreaction.
 23. The polymer according to claim 1, wherein, when R¹ or R²denotes aryl, heteroaryl, aryloxy or heteroaryloxy with 4 to 20 ringatoms which is optionally substituted, the optional substituent ishalogen or one or more alkyl or cyclic alkyl groups, and where R⁰ andR⁰⁰ independently denote H or alkyl with 1 to 12 C-atoms.
 24. Aformulation comprising a mixture or polymer blend according to claim 11,and one or more solvents.
 25. A charge transport, semiconducting,electrically conducting, photoconducting or light emitting materialcomprising a mixture or polymer blend according to claim 11.